Photo of vehicle that may have started Cuesta Fire is released

Update, 6 p.m. Tuesday, Aug. 25

The Cuesta Fire is 90 percent contained as of 6 p.m., according to Cal Fire. The fire has burned 2,446 acres, and 1,071 personnel are still on the scene.

Update, 10 a.m. Tuesday, Aug. 25

The Cuesta Fire south of Santa Margarita remains at 85 percent contained as of 7 a.m. Tuesday, according to Cal Fire, with 1,326 personnel continuing to work the blaze.

Crews continue to make outstanding progress in the Water Canyon, staying directly at the fire’s edge, according to an incident update.

Other areas of the fire are now being mopped up and patrolled. Officials said the fire burned 2,446 acres, not 3,500 acres as previously reported. The fire acreage data gathered by aircraft was limited by dense tree canopy, heavy smoke and local coastal fog.

On Monday, crews were able to access areas of the fire that they weren’t able to reach before and took steps to diminish hot spots in dense vegetation. Cal Fire said 122 firefighters were affected by poison oak in areas of thick vegetation.

Also, as high pressure continues to remain over the fire area, higher temperatures and shifting winds still pose a threat for increased fire activity within the wilderness, officials said.

Cal Fire released a photo Monday of a vehicle believed to have started the Cuesta Fire: a white pickup truck towing a trailer and a Volkswagen Beetle. Investigators believe the truck, traveling north on Highway 101, was experiencing a mechanical issue that ignited dry vegetation on the side of the freeway.

Anyone with information about the vehicle is asked to call the arson hotline at 800-468-4408. Callers can remain anonymous.

Update, 6:15 p.m. Monday, Aug. 24

The Cuesta Fire was 85 percent contained as of 6 p.m. Monday. Authorities hope to have the fire 90 percent to 95 percent contained by Wednesday, according to a Cal Fire spokesman.

Forty-five hand crews and 1,326 personnel are battling the blaze, which has burned 2,446 acres just south of Santa Margarita. According to a Cal Fire spokesman, the amount of acreage burned by the fire was originally overestimated due to its scattered nature.

Update, 11 a.m. Monday, Aug. 24

The Cuesta Fire is now 80 percent contained.

The 3,500-acre fire just south of Santa Margarita is expected to be fully contained by Wednesday. Fifty-three hand crews and 1,547 personnel are battling the blaze.

Cal Fire advises residents that smoke may be visible and temperatures in the area of the fire are expected to reach 86 degrees. These high temperatures and prolonged drought conditions make vegetation highly flammable.

“The fire continues to creep and smolder through dense vegetation and steep canyons within the southeast portion of the fire,” Cal Fire stated in a press release. “Firefighters work to maintain safety as they construct hand lines in deep drainages that can be dangerous to firefighters as they can’t see the main body of the fire.”

The Los Padres National Forest has closed the Santa Lucia Wilderness to the public as a result of the fire.

Update, 9 p.m. Sunday, Aug. 23

Warm weather will continue to be a challenge for firefighters battling the Cuesta Fire on Monday, Cal Fire spokesman Bennet Milloy said Sunday. With the 3,500-acre fire still 75 percent contained, Milloy said the weather and the dense vegetation where the fire is burning will be the fire crews' biggest challenges overnight and into Monday.

Cal Fire said Sunday that it will be sending 10 engines to Washington state to help battle the wildfires in the Pacific Northwest. However, none of those engines will be from the Cuesta Fire crews, Milloy said.

Update, 6:25 p.m. Sunday, Aug. 23

The Cuesta Fire was 75 percent contained Sunday evening, as crews faced hotter weather throughout the day.

Cal Fire spokesman Bennet Milloy said Sunday was a testing day with the transitional weather patterns. As the weather warms up, relative humidity decreases and small pockets of smoldering fire can become active and start to smoke or flame again.

High pressure is keeping the marine layer off the higher perimeter, making the fire harder to fight. The grass burns easier in the morning without the dampness from an overnight marine layer.

Milloy said there is pretty minimal fire behavior; the fire is creeping into deep canyons, which are difficult to access and dangerous to put crews in.

The firefighters are facing a number of challenges: There is a large amount of dry fuel for the fire from the drought, Milloy said. The terrain is also difficult — it takes extensive time to get crews engaged in the fire, and it’s a coordinated effort, which makes the progress slow. It also takes a long time to work through the dense vegetation.

There are an estimated 1,547 firefighters working the fire, but Milloy said that they are starting to make crews available to assist with other fires.

The 3,500-acre fire is expected to be fully contained by Wednesday.

Update, 7:20 a.m. Sunday, Aug. 23 

The Cuesta Fire remained 70 percent contained Sunday morning. But a high pressure system expected to build during the day -- bringing higher temperatures and lower relative humidity -- poses additional challenges for firefighters in holding the containment lines, Cal Fire reported.

The fire crept minimally overnight Saturday.

The slow lane of northbound Highway 101 remains closed for fire crews and equipment in the area. An estimated 1,710 firefighters were still working the 3,500-acre fire.

Update, 6:40 p.m. Saturday, Aug. 22 

Firefighters were closing in on the Cuesta Fire on Saturday, thanks to favorable weather and hard work, keeping the burn area to 3,500 acres and bringing containment up to 70 percent by evening.

Fire crews made significant headway in creating fire breaks in the southern area of the 3,500-acre burn area, where flames still torch the rugged terrain in the Santa Lucia wilderness area, Cal Fire spokesman Shawn Hughes said.

"The crews have continued to make great progress because of favorable weather conditions and their aggressive firefighting efforts," Hughes said. "Lower temperatures and increased relative humidity overnight is assisting in the firefighting."

The southern edge of the fire continues to burn with flames running uphill and into steep drainage areas, Cal Fire officials said, which “will continue to challenge firefighters” as hand crews focus on establishing containment lines in the steep, heavily vegetated terrain.

About 150 firefighters were released on Saturday, leaving 1,710 firefighters still working the fire. One helicopter also was diverted elsewhere, leaving six available on the Cuesta Fire. No new injuries have been reported since one firefighter suffered lacerations on the stomach Thursday. One structure has been destroyed.

Earlier in the week, fire officials estimated the fire would be fully contained by Wednesday or later. Hughes said that estimate has not been revised.

Update, 10:30 a.m. Saturday

Firefighters are continuing to make progress on the Cuesta Fire, with 55 percent containment achieved by Saturday morning, Cal Fire announced. The main focus of firefighting efforts continues to be along the southern boundary of the 3,500-acre burn area. 

The number of firefighters working the fire remains at 1,858, Cal Fire said.

Update, 10:35 p.m. Friday

The Cuesta Fire remains at 3,500 acres and 50 percent containment, according to Cal Fire spokesman Shawn Hughes.

Crews are continuing to make progress against the blaze because of favorable weather conditions, Hughes said.

There is still one injury from the fire, one structure burned and two structures threatened, Hughes said.

Hughes was unable to provide further information about the threatened structures.

Update, 7:35 p.m. Friday

Morning clouds, cooler temperatures and double the firefighting personnel all have aided efforts to gain control of the Cuesta Fire, which remained at 3,500 acres for a second straight day but with containment escalating to 50 percent by Friday evening.

No new details on the firefighter who suffered stomach lacerations Thursday were available, and no other injuries were reported Friday.

While Cal Fire officials were pleased with the progress, “that doesn’t mean we’re out of the woods,” said Koby Johns, a Cal Fire spokesman. “We’re still very concerned about the southern portion” of the burn area in the Santa Lucia wilderness area, he said.

An additional 250 firefighters arrived Friday, bringing the total to 1,858 personnel. With 17 other wildfires burning across California, the decision was made to release the two air tankers that had been dropping retardant on the Cuesta Fire this week. Seven helicopters continued to drop water throughout the day Friday.

The Santa Lucia wilderness area at the southern edge of the fire “is really the problem child of this fire right now,” Cal Fire spokesman Bennet Milloy said. “It’s very steep, with a lot of timber and a lot of heavy brush, and those things burn hot. But the fires are kind of just gutting around in the valleys, not a lot of activity. So we’ve got hand crews down there clearing the brush and working down there. That’s where I expect we’ll be into the weekend.”

Milloy said bulldozers and hand crews have cut fire lines and portable water tanks have been hauled in so that long lines of water hoses can be snaked into the rugged area. Still, “they feel the area is still threatened,” he said. “There are a lot of pockets of unburned vegetation.”

Cal Fire officials said progress was continuing to be made in cutting fire lines into the Trout Creek and Lopez Creek drainage areas.

While the air tankers are no longer fighting the Cuesta Fire, more ground equipment was brought in Friday, adding about 30 more engines to a total of 122, doubling the number of hand crews to 59 and also doubling the number of bulldozers to 27. Nine water tenders are delivering water to the temporary tanks.

That area of the Los Padres National Forest was closed to the public Thursday until Oct. 1 because of continuing fire threat. Closures include the Upper Lopez, Hi Mountain and Sulphur Pot campgrounds; Little Falls, Big Falls, Rinconada, Trout Creek and Upper Lopez trails; Hi Mountain Lookout and the Garcia Ridge OHV trail.

Information is still scarce on a structure destroyed by the fire on Thursday, but Milloy said it was an outbuilding.

“That could mean it was anything from a shed to a barn, but we do know that it was not a residence,” he said.

Also on Friday, Cal Fire investigators said they had exhausted all earlier leads in identifying the vehicle that is suspected of starting the Cuesta Fire on Sunday evening and appealed to the public for help.

Investigators said Monday they believe a vehicle having some kind of mechanical problem was traveling north over the Cuesta Grade and ignited dry vegetation next to the road. The fire was reported about 6:12 p.m. Sunday. 

The same vehicle is suspected of also starting a fire on the uphill stretch of Highway 101 at Nojoqui Grade in Santa Barbara County and a fire on an uphill section of Highway 41 east of Highway 101 in San Luis Obispo County. The fires all started within the time it takes to drive northbound on the route, Cal Fire Capt. Kevin McLean said.

“We’ve gotten some people calling” reporting possible vehicles, McLean said. “We’ve ruled them out because they were going in the opposite direction. We’ve exhausted all our leads at this point.”

Anyone who saw a vehicle heading north on Highway 101 with mechanical trouble, dragging a chain or that could have been involved in starting a fire on Cuesta Grade between 5:30 p.m. and 6:40 p.m. Sunday is asked to call the Cal Fire Arson Hotline at 800-468-4408. Callers may remain anonymous.

McLean said investigators don’t believe the fires were deliberately set.

“We believe that it’s not arson,” he said. “The reason we have people calling the arson hotline is because it’s staffed 24-7.”

Update, 6:50 p.m. Friday

Cal Fire reports the Cuesta Fire remains at 3,500 acres burned for a second straight day, but containment has increased to 50 percent. More information to come.

Update, 2:40 p.m. Friday

Cooler temperature, low clouds and nearly double the personnel all have vastly helped firefighting efforts on the Cuesta Fire, Cal Fire spokesman Bennet Milloy said.

"I think we could be approaching a turning point in this fire," he said. 

The majority of firefighting continues to be taking place on the southern part of the fire, in the Santa Lucia wilderness area, he said, after firefighters stopped the blaze from advancing north toward the town of Santa Margarita earlier in the week.

By Thursday evening, the number of firefighters had jumped to more than 1,600 -- up from fewer than 900 that morning.

The wilderness area to the south is "really the problem child of this fire right now," Milloy said. "It's very steep, with a lot of timber and a lot of heavy brush, and those things burn hot. But the fires are kind of just gutting around in the valleys, not a lot of activity. So we've got hand crews down there clearing the brush and working down there. That's where I expect we'll be for the rest of today and into the weekend."

Information is still scarce on the structure destroyed by the fire, but Milloy said it was an outbuilding.

"That could mean it was anything from a shed to a barn, but we do know that it was not a residence," he said. 

CalFire lists two other structures as threatened, but Milloy said there could possibly be more.

"I don't know specifically with this area, but with a lot of other fires I've worked on, there have been structures that we don't know are there until the fire sort of clears out the area around it," he said. "This entire area will have to be scouted after, and there could be more sheds or abandoned cabins revealed."

Update, 1:20 p.m. Friday

One structure was destroyed by the Cuesta Fire on Thursday, Cal Fire spokesman Rich Brocchini confirmed, though he did not know where the structure was located or whether it was a home or other type of building.

"We're expecting an update on that later in the day, because it is something we have been getting a lot of questions about," he said. "But as of right now, we don't have any more information on the structure."

Cooler temperatures have helped to keep the fire at 3,500 acres with 35 percent containment, and forward progress of the fire has been stopped.

"We've been told that there is no more forward progress on the fire, so that's good," Brocchini said. "Our firefighters are out there checking on hot spots and making sure nothing else flares up right now."

Because the fire does not appear to be growing, the decision was made Thursday to release its two air tankers to fight other fires in the state. Seven helicopters that drop water onto the fire are still available and being used, Brocchini said.

While the air tankers are no longer fighting the Cuesta Fire, more ground equipment was brought in, including quadrupling the number of water tenders to 16, adding about 30 more engines to a total of 122, and nearly doubling the number of hand crews to 51.

Brocchini also had no new details on the firefighter who suffered stomach lacerations Thursday. No other injuries have been reported.

Update, 6:30 a.m. Friday

The Cuesta Fire is still at 3,500 acres and is now 35 percent contained, according to Cal Fire.

The number of firefighters battling the blaze doubled Thursday, said Cal Fire spokeswoman Toni Davis, because resources became available.

“We put in our orders for what we would like to receive,” Davis said, referring to the number of firefighters needed. “With all the fires going on in this state, it’s difficult to get them right away.”

With favorable weather - including helpful low clouds over the fire - and extra personnel, Davis said crews are getting the upper hand. An infrared flight showed minimal spread of the blaze.

“I think we’re doing real well,” Davis said. “We’re making real headway.”

Update, 7:10 p.m. Thursday

With the Cuesta Fire continuing to burn south of Santa Margarita for a fifth day, the number of firefighters battling the blaze was nearly doubled on Thursday.

By evening, 1,610 firefighters were on scene, up from about 882 Thursday morning, Cal Fire spokesman Karl Kolodzik said. The size of the burned area remained unchanged Thursday at 3,500 acres, while containment increased over the course of the day to 30 percent by 6:30 p.m.

One firefighter was injured, with minor cuts to his stomach area caused when he lost his footing in steep terrain, Kolodzik said.

The most active area of the fire continued to be along the southern edge, where crews were challenged by steep terrain, extremely dry vegetation and toppling oak trees that posed a severe danger to firefighters.

“The trees are a major issue in this fire,” Cal Fire spokesman Bennet Milloy said. “It’s changing the way we’re fighting the fire. These massive, beautiful oak trees are so drought stressed that they’ve lost their root structure and are falling over. That’s just too dangerous at night, when firefighters can’t see them.”

In wooded areas, firefighters have been forced to retreat during the night and concentrate on maintaining the perimeter fire lines, he said. Ordinarily, they would remain in the active fire areas to continue to try to make headway against the flames. In open grassy areas, firefighters are continuing to fight the flames through the night, Milloy said. 

A priority on Thursday and continuing on Friday will be gaining control in the Water Canyon area at the southern edge of the fire, Milloy said. Firefighters were able to get approval to use bulldozers in the wilderness canyon, where mechanized equipment is usually banned to protect wildlife and prevent erosion.

Milloy said fire officials continue to anticipate that full containment of the Cuesta Fire could be Wednesday or later.

“This is going to be a little bit of a marathon and not a sprint,” he said. “It doesn’t seem like anyone will be going home soon.”

While firefighters continued to try to halt the fire from advancing further to the south, the town of Santa Margarita was returning to normal on Thursday, as the local elementary school held its first day of classes and the Atascadero Unified School District made plans to resume regular bus routes in the area on Friday.

Update, 12:15 p.m. Thursday

Water is a critical tool in both the ground and air attack to battle the Cuesta Fire.

Firefighters are relying on three water sources: Santa Margarita Lake, Lake Nacimiento and the community of Santa Margarita.

The water from Santa Margarita Lake is being pulled from the lake's booster reservoir, located adjacent to Highway 101 southwest of Santa Margarita, said Jeff Lee, capital projects manager for San Luis Obispo County’s public works department. It holds 3 million gallons of water.

The booster pump station pumps water from the lake — also called the Salinas Reservoir — over the Cuesta Grande and into San Luis Obispo, which uses it as one of its water sources. The Salinas Reservoir is currently 13.8 percent full.

The county also has installed a modified hydrant to pull water from its share of the Nacimiento Water Project. Lee said the hydrant is located at the west end of Santa Margarita. That water use will be metered so county officials will know exactly how much water was used.

The third source of water comes from the community of Santa Margarita, which relies on two groundwater wells. Lee said that water source would only be used if necessary. But some water has been used to make sure a half-million gallon storage tank remains full.

Lee said 325,000 gallons of water was used Monday through Wednesday to maintain a full tank. The community of Santa Margarita, with its approximately 1,200 residents, used about 275,000 to 300,000 gallons of water during that same time period.

Update, 10 a.m. Thursday

As of Thursday morning, Cal Fire was reporting no firefighter injuries, spokesman Bennet Milloy said. Injuries such as bumps, bruises and scratches are common, he said, and wouldn't be reported as official injuries.

"We report when a firefighter physically loses time from work for a significant reason," Milloy said. "So as of this morning there were zero injuries."

According to Cal Fire's incident information website, there are currently about 900 firefighters assigned to the Cuesta Fire. The report also said two structures are threatened.

Update, 6:30 a.m. Thursday

The Cuesta Fire remained at 3,500 acres burned and 20 percent contained Thursday morning, according to Cal Fire.

Fire behavior overnight was pretty minimal, said Cal Fire spokesman Bennet Milloy.

“It was a pretty quiet night,” Milloy said, adding that there was some isolated pockets of torching, such as a single tree burning out. “But none of that stuff is really a threat to the lines.”

Crews were able to stay engaged on the fire permiter, Milloy said.

The risk to Santa Margarita continued to decrease overnight, Milloy said, and the containment lines are holding well.

“Parents should feel safe and confident sending their children to school,” he said.

There were no reported problems after evacuees were allowed to return to their homes Wednesday evening, Milloy said.

Weather on Thursday is expected to be very similar to Wednesday, Milloy said. Sometime in the afternoon a more prominent smoke column will likely rise.

“It will be a little more obvious as the fire heats up, but people shouldn’t be frightened by that,” Milloy said.

A priority for Thursday is the Water Canyon area, Milloy said. Firefighters were able to get approval to use bulldozers in the canyon, which is usually against the rules. Wilderness areas are usually off-limits to mechanized equipment in order to protect animals and plants. Dozer lines can also lead to erosion and people trying to use the lines for off-roading after the fire is out.

Getting the approval for bulldozing was a "huge success," Milloy said.

Update, 11 p.m. Wednesday

Cuesta Fire activity should be somewhat minimal overnight because of the humidity and coolness provided by the marine layer coming in, Cal Fire spokesman Bennet Milloy said about 10:15 p.m. Wednesday.

"The fire is still burning pretty actively down in the Water Canyon area, which is our biggest concern right now," he said. "The northern portion of the fire toward the city of Santa Margarita is looking very promising, that's why the evacuation was lifted at 5 p.m."

Milloy said their tactics change dramatically at night because aircraft are too challenging to be used for firefighting in the dark.

"During the day when the fire picks up more steam, we have to use a lot more aircraft to cool it down so we can put crews right up against the edge — one foot in the black, one foot in the green," Milloy said. "At night, we can't use aircraft, so when it cools down, it's an opportunity for us to get direct on the fire line without aircraft, because when the humidity comes up and the temperature comes down, it's kind of like a blanket that sits on the fire. The fire doesn't really get very active, it doesn't wanna move around."

Fire behavior Wednesday night and early Thursday morning is expected to consist mostly of "isolated torching" at higher elevations where it's warmer and drier.

Update, 9:30 p.m. Wednesday

Nearly 900 firefighters from around the state continued to battle the Cuesta Fire on Wednesday even as the blaze grew to 3,500 acres by evening.

Still, containment also grew to 20 percent and the most active area of the fire was to the southeast, away from the town of Santa Margarita and the 339 homes that had been threatened Tuesday.

The changing face of the fire prompted Cal Fire officials to cancel an evacuation order at 5 p.m., allowing residents to return home and Santa Margarita Elementary School officials to plan to welcome students to the first day of classes on Thursday — a day later than originally scheduled.

An evacuation center at Santa Rosa Academic Academy in Atascadero closed down once the order was lifted.

Cal Fire officials said they don't expect to be able to fully contain the fire for another week, because of the steep terrain, warm weather and moderate winds as the flames march through drought-seared vegetation.

On Wednesday, firefighters were aided by six helicopters and three air tankers dropping water and fire retardant on the blaze. On the ground were 89 engines, 26 hand crews, nine bulldozers and four water tankers.

About 100 residents flocked to a community meeting Cal Fire and National Forest Service officials held Wednesday evening at Santa Margarita Elementary School.

Cal Fire/San Luis Obispo Chief Robert Lewin told the crowd that Santa Margarita is likely "out of the woods," but asked residents to abide by any future evacuation orders. Of the historically dry conditions, Lewin said "we've not seen these conditions ever in our careers."

Lewin said the three fires that initially comprised the Cuesta Fire compounded the problem for attack crews who struggled to contain six fire flanks.

“It gave an opportunity for the fire to outpace us,” Lewin said.

As of Wednesday, firefighters are dealing with steep terrain as they continue to fight more active areas on the southeastern side of the fire.

“It still takes a long time for them to put in good lines in that terrain,” said Fire Capt. Steve Kaufmann of the Ventura County Fire Department.

Also, Kaufmann said, firefighters normally expect fire activity to increase between noon and 4 p.m. — the hottest part of the day.

In response to a question from a community member, Lewin said he felt confident that flames wouldn’t reach the other side of Pozo Road.

“There’s a lot of protection between Pozo Road and the fire,” he said.

With Santa Margarita Elementary heading back to school Thursday, another resident asked about the Atascadero Unified School District’s plans to evacuate students in an emergency.

“We will be extremely cautious and follow any directions from incident commanders,” said Curt Eichperger, the district’s assistant superintendent of human resources. “If there are concerns about a shift in the weather pattern, then we will immediately bring buses out.”

Students could be bused to two possible locations, which Eichperger did not disclose Wednesday. 

Residents clapped repeatedly in gratitude to the firefighters who have kept the flames from reaching their town.

Other Cal Fire officials talked about the challenges firefighters are facing: drought, falling trees, and resources stretched thin as fires erupt across the state. Some firefighters have been working more than a month straight on fires, they said.

Lewin choked up as he talked about three firefighters who died Wednesday battling a wildfire in northern Washington state.

Earlier in the day, piles of white-hot ash could be seen among areas of blackened underbrush as Cal Fire spokesman Bennet Milloy drove up the hillside south of the staging area in Santa Margarita.

Some firefighters and two California Army National Guard teams spent the day mopping up burned areas to prevent ash from blowing and igniting dry grass.

“We’re just making sure we do 100 percent mop-up,” said San Benito/Monterey Cal Fire Capt. Mitch Colombo. “We’re making sure the heat is out of it.”

As Milloy drove around the northeastern perimeter of the fire, he pointed out a drought-stricken tree that had burned and collapsed in the fire, with ash surrounding its base. The dead and dying oak trees, along with other dry fuel, are main concerns for firefighters. “We heard them falling all night long,” Milloy said of the oak trees.

That poses significant danger to firefighters on the ground. A firefighter from San Luis Obispo County was paralyzed after he was pinned under a massive oak tree in July while battling a small wildland fire in Tulare County.

Two other firefighters have died while battling California blazes recently. But taking extra precautions make it more difficult to fight the fire. So far, no one has been injured in the Cuesta Fire, something Milloy called “a huge success.”

Other concerns include wind direction.

Fire crews were hoping the winds would continue to keep the fire burning away from residential areas, Milloy said.

About seven residents stayed at the Red Cross shelter at Santa Rosa Academic Academy on Tuesday night and the operation had to adjust a bit Wednesday morning when kids returned for the first day of school, volunteer Cindy Osgood said.

Temporary fences were installed to cordon off the shelter area from the rest of the school population, and the Red Cross reduced the space being used in the cafeteria so that students could get access to their meals.

Although the evacuation order was canceled, already-burned areas south of Santa Margarita were still not considered contained because even a so-called cold area of the fire could pose a threat to the control lines.

Smoke from the more active areas of the Cuesta Fire could be seen to the south and east on Wednesday. A smoke column from the southern portion of the fire started to build about 12:30 p.m.

Later in the afternoon, Milloy said a smoke column was drifting toward Park Hill Road. The smoke could be deceiving, however, as the fire was much closer to the southwest corner of Santa Margarita. Bulldozer work was continuing on the east and west sides of the fire.

At the Cal Fire staging area in Santa Margarita, two crews from the California Army National Guard arrived to help with clean up and free up firefighters to concentrate on the more active areas of the fire.

Twelve crews in total were activated at the end of July; the two crews that arrived Tuesday had already helped out at two separate fires in Northern California. Once their service ends — they can only be on the line for 30 days — they could be replaced by other crews, said Cal Fire Capt. Ken James, who assists with their training.

About 24 National Guard members waited at the staging area in Santa Margarita to learn where they would spend their day.

“For us, coming from civilian work — a lot of us have desk jobs — to turning shovels and hand tools, it's been exciting but physically demanding,” said First Lt. Raul Briseno, who works for San Bernardino County.

Update, 8 p.m. Wednesday

About 100 residents flocked to a community meeting that Cal Fire and National Forest Service officials held Thursday evening at Santa Margarita Elementary School.

Cal Fire/San Luis Obispo Chief Robert Lewin told the crowd that Santa Margarita is likely "out of the woods," but asked residents to abide by any future evacuation orders. Of the historically dry conditions, Lewin said "we've not seen these conditions ever in our careers."

Residents clapped repeatedly in gratitude to the firefighters who have kept the flames from reaching their town.

Other Cal Fire officials talked about the challenges firefighters are facing: drought, falling trees, and resources stretched thin as fires erupt across the state. Some firefighters have been working more than a month straight on fires, they said.

Lewin choked up as he talked about three firefighters who died Wednesday while fighting a fire in northern Washington state.

Update, 7 p.m. Wednesday

The Cuesta Fire has burned 3,500 acres and is 20 percent contained, Cal Fire officials said in a new update. Full containment is expected in another week, on Aug. 26. Officials have revised the number of firefighters working the blaze to 882 personnel. No homes have burned and no injuries have occurred.

The southeastern section of the fire approaching Los Padres National Forest became more active Wednesday afternoon, burning in heavy, drought-stressed vegetation.

"Steep terrain, warm weather and moderate winds, combined with extreme drought conditions will continue to present containment challenges," the Cal Fire update noted.

On Wednesday, firefighting efforts consisted of six helicopters, two air tankers, 89 engines, 26 hand crews, nine bulldozers and four water tankers, Cal Fire said.

Update, 6 p.m. Wednesday

The Red Cross evacuation center at Santa Rosa Academic Academy in Atascadero was closed after the evacuation order was lifted at 5 p.m. Wednesday, according to the county Office of Emergency Services.

Update, 5 p.m. Wednesday

Fire officials say that a large plume of smoke that is suddenly visible from the Cuesta Fire is from flareups from within the fire's containment area. Helicopters and ground crews have been dispatched.

Update, 4:40 p.m. Wednesday

Evacuation orders for Santa Margarita and Miller Flat are to be lifted at 5 p.m., according to Cal Fire.

Residents returning to their homes are asked to be careful of fire crews in the area.

Update, 2:30 p.m. Wednesday

Piles of white-hot ash could be seen among areas of blackened underbrush as Cal Fire spokesman Bennet Milloy drove up the hillside south of the staging area in Santa Margarita on Wednesday.

Some firefighters and two California Army National Guard teams spent the day mopping up the burned areas to prevent ash from blowing and igniting dry grass. The area is still not considered contained because even this so-called cold area of the fire could pose a threat to the control lines.

“We’re just making sure we do 100 percent mop-up,” said San Benito/Monterey Cal Fire Capt. Mitch Colombo. “We’re making sure the heat is out of it.”

Smoke from the more active areas of the Cuesta Fire could be seen further south and east. A smoke column from the southern portion of the fire started to build about 12:30 p.m.

Cal Fire will release updated information later Wednesday evening on the estimated size and containment of the fire. Initial estimates put the number of firefighters working the blaze at about 1,000, but that number has been revised to about 800, Milloy said.

As he drove around the northeastern perimeter of the fire, Milloy pointed out a drought-stricken tree that had burned and collapsed in the fire, with ash surrounding its base.

He called black circles on trees “cat’s eyes,” which indicate the interior of the tree had burned and would likely fall — if not soon, due to wind, then later this year if the area receives much-needed rain.

Update, 11:30 a.m. Wednesday

The Red Cross shelter at Santa Rosa Academic Academy in Atascadero remains open for evacuees from the Cuesta Fire.

The operation had to adjust a bit this morning when kids returned for the first day of school, volunteer Cindy Osgood said.

Temporary fences were installed to cordon off the shelter area from the rest of the school population, and the Red Cross reduced the space being used in the cafeteria so that students could get access to their meals.

About seven clients are currently staying at the facility.

At the Cal Fire staging area on Wednesday morning, two crews from the California Army National Guard arrived to help with clean up and free up firefighters to concentrate on the more active areas of the fire.

Twelve crews in total were activated at the end of July; the two crews which arrived Tuesday had already helped out at two separate fires in Northern California. Once their service ends -- they can only be on the line for 30 days -- they could be replaced by other crews, said Cal Fire Capt. Ken James, who assists with their training.

About 24 National Guard members waited at the staging area in Santa Margarita to learn where they would spend their day.

"For us, coming from civilian work -- a lot of us have desk jobs -- to turning shovels and hand tools, it's been exciting but physically demanding," said First Lt. Raul Briseno, who works for San Bernardino County.

Update, 9 a.m. Wednesday

Firefighters were able to gain some good ground on the north side of the Cuesta Fire overnight, which brought containment up to 15 percent, according to Cal Fire spokesman Bennet Milloy.

Drought-stricken fuel, including dead and dying oak trees, are main concerns for firefighters, Milloy said.

"We heard them falling all night long," Milloy said of the oak trees.

That poses significant danger to firefighters on the ground. A firefighter from San Luis Obispo County was paralyzed after he was pinned under a massive oak tree in July while battling a small wildland fire in Tulare County. Two other firefighters have died while battling California blazes recently.

"We definitely don't want to repeat that," Milloy said.

However, taking extra precautions make it more difficult to fight the fire.

Other concerns include wind direction.

Fire crews are also hoping the winds stay in a northwest direction, Milloy said. At this point the fire is burning away from residential areas and there are no concerns for additional evacuations.

Evacuations remain in effect for some Santa Margarita residents. Fire officials will reevaluate the order this afternoon after observing fire and weather conditions.

Milloy cautioned that it would probably be at least another 24 to 48 hours after the reevaluation before residents could return home, but added trying to get people back into their houses is a top priority.

Update, 8:30 a.m. Wednesday

Charter Communications customers in the North County might see service interrupted due to the Cuesta Fire, according to the San Luis Obispo County Office of Emergency Services.

Cable, internet and phone service might go out temporarily if cable lines are damaged.

Charter customers south of the grade should not be affected.

Update, 6 a.m. Wednesday

The Cuesta Fire remained at 2,500 acres burned Wednesday morning, according to Cal Fire. It is now 15 percent contained.

While persistent onshore winds have kept smoke from the Cuesta Fire away from San Luis Obispo and coastal communities like Morro Bay and Pismo Beach, the winds could reverse Wednesday morning, according to meteorologist John Lindsey. Light offshore winds could mean those communities could start seeing smoke.

Update 10:15 p.m. 

Firefighters are still actively battling the Cuesta Fire overnight, Cal Fire spokesman Bennet Milloy said at 10 p.m.

"The good news is the temperature has gone down and the humidity has gone up a lot," he said. "This is a moment of opportunity for us."

Milloy said that with temperatures in the mid 60s and no wind, the flames are burning lower and slower, giving firefighters an advantage. The estimated burn area will be reassessed on Wednesday morning. At 6:30 p.m., 2,500 acres had burned and 10 percent was contained.

Update 7 p.m. Tuesday

Residents and business owners in Santa Margarita watched and waited while smoke billowed up a hillside about a half mile southwest of town on Tuesday, as the Cuesta Fire continued to burn for a third day.

With 339 homes threatened, a voluntary evacuation order remained in effect and Santa Margarita Elementary’s first day of school on Wednesday was canceled.

While winds blew the blaze close to town Tuesday, firefighters were able to maintain a wide fire break they had bulldozed out of the brush, keeping the flames from spreading to any homes or structures.

The fire had scorched 2,500 acres as of 6:30 p.m. and was 10 percent contained as it continued to burn in three separate blazes east of Highway 101. Two of the highway’s three northbound lanes on the Cuesta Grade remained open Tuesday, and Highway 58 through Santa Margarita was open in both directions.

Air quality countywide was affected so that even healthy people could be affected by particulates in the smoke, the county Air Pollution Control District warned.

Anyone experiencing a cough, shortness of breath, wheezing, exhaustion, light-headedness or chest pain should stop outdoor activity and seek medical attention, health officials said.

About 1,000 fire personnel fought the blaze Tuesday while at least three tanker planes dropped red fire retardant and six helicopters refilled water buckets from a Santa Margarita Lake booster treatment plant. The aircraft are required to quit flying a half-hour before sunset.

The voluntary evacuation order for Santa Margarita residents living south of Highway 58 was expected to remain in effect until at least Wednesday morning, Cal Fire spokesman Bennet Milloy said.

“The fire is going to burn actively through the night until we get the marine layer moving into the area,” he said.

Santa Margarita Elementary School delayed its opening day of classes because it lies within the evacuation area.

“This closure will remain in effect until local authorities lift the order,” the Atascadero Unified School District said in a statement. “AUSD’s No. 1 priority is the safety and well-being of our students, staff and community.”

Cal Fire officials said Tuesday evening that the fire is in an area that hasn't burned in about 30 years and is expected to continue to spread southeast in the Santa Lucia wilderness. A combination of steep terrain, hot weather and moderate winds, as well as extreme drought conditions mean spot fires in the Santa Margarita area also are possible. 

Many residents and business owners remained in Santa Margarita on Tuesday, despite the evacuation order.

Sophie Treder, a land law attorney who works out of an office at 22985 El Camino Real, one of the structures closest to the fire, stayed at work on Tuesday and spent much of the day providing ice for a bucket of sports drinks and water. Treder and others in her building offered up the beverages for the firefighters, who were stationed nearby off Wilhelmina Avenue. They felt the fire was far enough away not to evacuate.

“We have confidence in the firefighters,” Treder said. “And there’s really nothing in that area. It kind of looks like it’s blowing east, and there’s nothing but brush for miles.”

Fire officials were most concerned with increasing afternoon winds, which also had picked up Monday afternoon.

The flames burned across the eastern edge of the Cuesta Grade in an area of brush, oak trees and power lines.

A power line briefly smoldered about 11 a.m. from the ash that was raining down, and PG&E crews visited the site to monitor the situation and make sure power stayed on.

The winds alternated from blowing easterly to northerly during the late morning. Periodic northerly winds ushered the flames toward town, and a hillside between Highway 101 and town became consumed with smoke and flames during the course of an hour.

Planes were flying in at a more frequent pace by about 12:30 p.m., dropping water from buckets on hot spots near the freeway, holding the line where firefighters had bulldozed several hundred yards of flatlands to keep the flames from leaping toward the town.

The town is separated from the fire area by the break line and another hillside.

Cal Fire San Luis Obispo Station 12 Fire Capt. Amber Henderson said that firefighters have been challenged by steep terrain and extremely dry conditions.

“We were the first to respond on the first day, and because this fire was in three (locations), it was hard to contain,” Henderson said. “We couldn’t surround it easily or take as aggressive of an approach as we would have liked.”

INFO AT A GLANCE

Evacuation center: Santa Rosa Academic Academy, 8655 Santa Rosa Road , Atascadero. Pets welcome.

Fire information: Call the County Office of Emergency Services Assistance Center at 543-2444 to speak to a live operator. Or visit the OES website. Follow Cal Fire on Twitter, @CalFire_SLO

Air Quality: Check the county Air Pollution Control District website

Road closures: East Cuesta Road and West Cuesta Road from Highway 101, slow lane of northbound Highway 101, TV Tower Road

Update, 2:30 p.m. Tuesday

Business owners and residents of Santa Margarita waited and watched as smoke billowed up a hillside about a half of a mile south of town on Tuesday as the Cuesta Fire continued to burn and smolder.

Winds were blowing the blaze closer to town, but fire officials have been able to maintain their line of bulldozed brush to keep the fire from jumping.

Cal Fire officials said an evacuation remained in effect, though many homeowners and business owners stayed put.

Sophie Treder, a land law attorney who works out of an office at 22985 El Camino Real, didn't leave work even though the building is one of the structures closest to the fire.

Instead, she refilled ice for a bucket of water and Gatorade she and others in her building offered the firefighters.

Chad Tantum, of Straight Arroyo Customs, who shares office space with Treder, said they felt the fire was far enough away not to worry and remained at work.

“We have confidence in the firefighters,” Treder said. “And there’s really nothing in that area. It kind of looks like it’s blowing east and there’s nothing but brush for miles.”

The fire had burned 2,000 acres and was 10 percent contained as of Tuesday morning, with about 1,000 fire personnel on hand to combat the blaze.

“We’re most concerned about what will happen around 3 p.m. to 4 p.m. when the winds pick up,” said Bennet Milloy, a Cal Fire spokesman. “The winds strengthened around that time yesterday, and that’s why we aren’t lifting that evacuation order.”

Three separate blazes spread across the eastern edge of the Cuesta Grade, which is made up of brush, oak trees and power lines.

A power line briefly smoldered from the ash that was raining down, and Pacific Gas and Electric officials visited the site to monitor the situation and make sure power stayed on.

The winds alternated from blowing easterly to northerly during the late morning.

The northerly winds ushered the flames toward town, and a hillside between the Highway 101 freeway and town became consumed with smoke and flames during the course of an hour.

Planes flew in at a more frequent pace about 12:30 p.m., dropping water from buckets in hot spots near the freeway, holding the line where firefighters had bulldozed several hundred years of flatlands to keep the flames from leaping towards the town, separated by another hillside.

Cal Fire San Luis Obispo Station 12 Fire Capt. Amber Henderson said that firefighters have been challenged by steep terrain in places and extremely dry conditions.

“We were the first to respond on the first day and, because this fire was in three (locations), it was hard to contain,” Henderson said. “We couldn’t surround it easily or take an aggressive of an approach as we would have liked.”

Fire officials said that nobody is forced to evacuate, but they’re encouraged to do so as a safety precaution. Sheriff’s deputies gathered Tuesday to be prepared to usher people to safety if necessary.

An additional gauge of the acreage covered by the fire is expected later today, Milloy said.

“We typically do two updates on acreage burned per day,” Milloy said. “The next one might be around 8 p.m.”

The public may call the County Phone Assistance Center at 543-2444 for up-to-date emergency information regarding the Cuesta Fire or visit @CalFire_SLO on Twitter.

Update, 11:10 a.m. Tuesday

The Cuesta fire has remained at 2,000 acres burned with 1,000 fire personnel on staff and 339 Santa Margarita residents in evacuation notice.

Cal Fire spokesman Bennet Milloy said three separate blazes are continuing to burn east of Highway 101 and south of Santa Margarita.

Milloy said winds will pick up about 3 p.m. Tuesday and firefighters are trying to control the spread.

The closest flames to Santa Margarita are about a half-mile south.

Santa Margarita Elementary School is on standby to hear whether school will be open for its first day Wednesday.

Milloy said the goal is to have school take place as planned, but Cal Fire will know more after the afternoon response.

Fire officials have faced steep terrains and extremely dry conditions that have made their response challenging.

Update, 11 a.m. Tuesday

A handful of evacuees from Santa Margarita are spending the day at the Red Cross shelter at the Santa Rosa Academic Academy in Atascadero.

Marilyn Oedekerk and Gina Travelstead were evacuated from a trailer park in Santa Margarita around 7:30 Monday night.

"It was raining ashes on us," Travelstead said, while sitting on a cot with her toy poodle, Sally. When an officer showed up and told her it was time to go, she said she was "terrified."

"You're shakin' in your boots even though you're not wearing boots."

Oedekerk, who lives nearby with a friend, had time to grab her medications, a change of clothes and some valuables before leaving. Her friend went to stay with family in Atascadero while she headed to the shelter.

"It was a wonderful group effort getting everyone evacuated," she said.

Oedekerk was grateful for the assistance provided by the volunteers in Atascadero.

"This was stocked with cots, blankets, water, food. ... I was just so impressed — a five-star Red Cross endeavor," she said, while relaxing outside with her 14-year-old dog Reba Marie Flynt.

As of Tuesday morning, Red Cross volunteer Cindy Osgood of Templeton said the shelter has served 29 clients so far, including 23 who spent the night. The four workers on 12-hour shifts also handed out 15 comfort kits filled with toiletries.

The operation was set up in the cafeteria of the school, which opens for the new year on Wednesday. Osgood said the shelter was well stocked with food, water and physical goods and asked that anyone wishing to donate call 800-Red-Cross or visit redcross.org.

The North County Humane Society is also providing temporary shelter for cats. Call 466-5403 for more information.

Update, 9 a.m. Tuesday

Cal Fire says the evacuation order for parts of Santa Margarita will remain in effect due to potential spot fires. Officials will reevaluate the orders this afternoon.

Update, 5:30 a.m. Tuesday

Crews were able to keep the Cuesta Fire from hitting Santa Margarita overnight after it came within a quarter-mile of town.

“The good news is that the firing operation on that road last night, which was a last ditch effort before it hit the town of Santa Margarita, was successful,” said Cal Fire Incident Cmdr. Rob Lewin.

Fire officials will review evacuation orders this morning, Lewin said, and determine if some people can return to their homes.

"We're thinking about them," Lewin said of evacuees.

The blaze is now at 2,000 acres and is 10 percent contained, Lewin said, but added that mapping and acreage could be off until a helicopter is able to get up this morning and get a more accurate view of the fire lines.

All of Highway 101 remains open, Lewin said.

The county Air Pollution Control District has also released a warning because smoke and ash are creating poor air quality in northern San Luis Obispo County. Skies north of the Cuesta Grade are hazy and fine particulate concentrations are higher than normal.

Changing wind and weather conditions make it difficult to predict which areas of the county may be most affected by smoke and ash from the fire. People, especially those with respiratory and heart conditions, should limit outdoor activity until the air clears.

Particulate levels in the smoke may be high enough that even healthy people could be affected, according to the APCD. If a cough, shortness of breath, wheezing, exhaustion, light-headedness or chest pain occurs, outdoor activity should be stopped and the affected person should seek medical attention.

Update, 11 p.m. Monday

Firefighters are working to prevent the Cuesta Fire from reaching Santa Margarita after it jumped containment lines on its eastern borders, according to Cal Fire Engineer Bennet Milloy.

At about 9 p.m. Cal Fire announced that the fire had come within about a half- to a quarter-mile of the town.

"We're actively engaged in structure protection and defense," said Milloy, stating that firefighters are optimistic about pushing the fire back from Santa Margarita. He then explained that fuel was being used to lead the fire away from town.

There are about 1,000 firefighters assigned to the 500-acre fire, which is 10 percent contained, according to Milloy. 

The fire crews are also utilizing about 20 hand crews, 40 fire engines, four bulldozers, six water tenders and four helicopters. Additional support has been ordered and is set to arrive over the next few days, according to government incident report website InciWeb.

Update, 8:30 p.m. Monday

Cal Fire is advising those who have not followed the evacuation order to do so. Cal Fire tweeted that firefighters are attempting to hold the fire to the road about a quarter mile away from Santa Margarita, but say that if they can't the fire will reach the town.

Evacuations were ordered for the part of Santa Margarita south of the railroad tracks and for all of Miller Flats. 

Evacuees can bring household pets with them to the evacuation center, according to the San Luis Obispo County Office of Emergency Services. 

Update, 7 p.m. Monday

The three fires burning on the Cuesta Grade have grown to about 500 acres, about 10 percent of which is contained as of early Monday evening.

Evacuations are still in effect. The San Luis Obispo County Office of Emergency Services wrote on Twitter that an evacuation center is being opened at the Santa Rosa Academic Academy at 8655 Santa Rosa Rd. in Atascadero.

Andrew Madsen, spokesman for the U.S. Forest Service, said from an emergency command post on Wilhelmina Avenue in Santa Margarita that fire crews were cautiously optimistic that weather conditions would be favorable to making progress on the different fires overnight.

"When the winds kicked up this afternoon, the fires really picked up on us," Madsen said, adding that a large percentage of the fires are affecting state and federal forestland.

As the sun began to set, heavy plumes of smoke remained in the sky, blocking aircraft from conducting a thorough survey of the area to determine an exact acreage of the fires.

He said crews hope to conduct that survey Tuesday morning.

However, he said that weather overnight, with the possibility of coastal weather conditions moving in and bringing greater humidity would assist firefighters.

"And it was about eight degrees cooler today, a trend we're hoping will continue tomorrow," Madsen said.

Milloy said that a temporary evacuation center had been set up in the La Poloma Park in Atascadero and as of early Monday evening none of the roughly 500 residents affected by evacuation efforts in Santa Margarita had begun showing up.

He said the center will remain open as long as is needed, and that officials had no reason to believe as of early Monday night that further evacuations would be needed.

"But then again, we did not plan for (today's) evacuation either," Milloy said. "There's still a risk onshore winds could send embers so we do want to rule anything out. Officials say that if any residents feel threatened, the best option is to self-evacuate.

Update, 6 p.m. Monday

An estimated 500 people and 350 homes in the Santa Margarita area were evacuated late Monday as a result of the Cuesta Fire, which had grown to 500 acres by early evening. Those affected were located south of the railroad tracks in the town.

A temporary evacuation center was set up at Paloma Creek Park in Atascadero, according to Cal Fire. Residents were strongly encouraged to obey the evacuation order for their own safety and the safety of firefighters, Cal Fire officials said.

The fire was burning east of Highway 101 near the Cuesta Grade, 8 miles north of San Luis Obispo. The fire started Sunday at 6:18 p.m. by a vehicle traveling up the Cuesta Grade that is suspected of causing two other blazes.

Cal Fire spokesman Bennet Milloy said the vehicle that sparked the Cuesta Fire also started the Grade Fire in Santa Barbara County near Buellton and the 12-acre Cholame Fire off of Highway 41.

The fires could have been started by sparks from a tow chain or an overheating catalytic converter, Milloy said.

Priorities for firefighters are to keep the fire out of the Santa Lucia Wilderness and protect power lines and communications towers, Milloy said.

As of 5 p.m. Monday, the Cuesta Fire had grown to 500 acres and was 5 percent contained. More than 300 firefighters were assigned to the fire with more on the way. Winds picked up early Monday afternoon and caused a spot fire to jump north of the fire lines, burning toward Santa Margarita. The rapid spread of that blaze prompted the evacuations, Milloy said.

Fire crews made good progress through Sunday night constructing fire lines on the northeastern edge of the fire. But the fire remained active overnight due to down-canyon winds that caused isolated torching of trees.

On Monday, crews continued building fire lines in the rugged, drought-stricken terrain. “Temperatures reached into the 80s and there was the potential for significant fire growth,” Milloy said.

Caltrans has suspended road work on the Cuesta Grade because the project is located within an active fire zone, spokesman Jim Shivers said.

Construction will resume when the Cuesta Fire poses no threat to the public or highway workers, he said. A project started last week to resurface Highway 101 in both directions from Reservoir Canyon Road to north of Cuesta Peak.

There was no road work over the weekend, but it was supposed to resume Monday morning.

The fire caused the closure of East Cuesta Road from Highway 101, West Cuesta Road from Highway 101, the slow lane on Highway 101 and TV Tower Road.

Communities around the fire area should expect to see smoke throughout the day and into the evening, Milloy said. During the day, upslope winds are expected to take smoke to higher elevations, but winds are expected to reverse and bring smoke down slope in the evening.

Update, 4 p.m. Monday

Cal Fire has announced evacuations in Santa Margarita south of the railroad tracks and in all of the Miller Flat area as a result of the Cuesta Fire. No evacuation center has been established yet.

A temporary evacuation center is reportedly being set up at Paloma Creek Park on Viejo Camino in Atascadero.

Update, 3:30 p.m. Monday

As of 3 p.m. Monday, the Cuesta Fire had grown to 300 acres and is 5 percent contained, according to Cal Fire. The fire grew because spot fires jumped the lines crews had built around the blaze.

Update, 10 a.m. Monday

A single vehicle is responsible for causing three fires in two counties, according to Cal Fire investigators.

Bennet Milloy, Cal Fire spokesman, said a vehicle sparked the 100-acre Cuesta Fire as well as the Grade Fire in Santa Barbara County and the Cholame Fire off of Highway 41. The fires could have been started by sparks from a tow chain or an overheating catalytic converter.

As of 8 a.m., the Cuesta Fire was 100 acres and 10 percent contained. Fire crews made good progress through the night constructing fire lines on the northeastern edge of the fire.

A firefighting crew of 250 people continued to fight the 100-acre Cuesta Fire on Monday morning which is burning east of Highway 101 on the Cuesta grade eight miles north of San Luis Obispo. Priorities for today will be to keep the fire out of the Santa Lucia Wilderness and protect power lines and communications towers, said Milloy.

The fire has caused the closure of East Cuesta Road from Highway 101, West Cuesta Road from Highway 101, the slow lane on Highway 101 and TV Tower Road.

Communities around the fire should expect to see smoke throughout the day and into the evening, Milloy said. During the day, upslope winds are expected to take smoke to higher elevations, but winds are expected to reverse and bring smoke down slope in the evening.

The fire remained active overnight caused by down canyon winds which caused isolated torching of trees. Today, crews will continue building fire lines and in the rugged, drought-stricken terrain.

“Temperatures should reach into the 80s today and there is the potential for significant fire growth today,” Milloy said.

Caltrans has suspended road work on the Cuesta Grade because the project is located within an active fire zone, spokesman Jim Shivers said.

Construction will resume when the Cuesta Fire poses no threat to the public or highway workers, he said. A project started last week to resurface Highway 101 in both directions from Reservoir Canyon Road to north of Cuesta Peak.

There was no road work over the weekend, but it was supposed to resume Monday morning.

Update, 5:30 a.m. Monday

The Cuesta Grade fire has grown to 100 acres, but crews have been able to hold the containment to 10 percent, according to Cal Fire.

The far right, slow lane on the northbound side of Highway 101 going over the grade remains closed this morning, according to the CHP. The other two lanes are open.

Update, 11 p.m. Aug. 16

Incident Cmdr. Robert Lewin said Sunday night that the Cuesta Grade fires are still estimated to total 40 acres. He said that crews will wait for daylight to do a proper scan of the area for a new estimate.

Lewin also said that there will be 150 people fighting the fire throughout the night.

"The fire is far from contained right now," he said. Cal Fire is still reporting that the fires are just 10 percent contained.

Lewin added that aircraft will return at 7 a.m. to help battle the blaze.

Update, 10 p.m. Aug. 16

Firefighters continue to battle the fires on the Cuesta Grade that broke out about 6:15 p.m. 

"The fire has been making runs up the slope," Incident Cmdr. Robert Lewin said Sunday night.

Lewin said firefighters were continuing efforts to contain the fire west of Mount Lowe Road, but that it had crossed over in several spots. Crews are working to contain those spot fires over the line.

Lewin said that one of the fires is north of the Cuesta Grade.

"That fire is a concern for us because it's burning an area that is very rough … over there on the north slopes," he said.

About 150 personnel were working on the fire Sunday night, with Lewin and others working to make plans for Monday's crews because they know the fire will continue into the morning. The fire is currently 10 percent contained.

Weather conditions are a concern for the fire crews.

"Our biggest concern also right now is if we have any offshore winds that surface in the a.m. hours," Lewin said. "So we're doing a spot weather forecast right now. We're having that done to see if we should expect some Santa Lucia winds for tomorrow morning. If so, that could cause us some problems with some downslope runs of the fire."

Two northbound lanes of Highway 101 remain closed, but Lewin said fire crews are working with the CHP to get one open. He also noted that people should anticipate heavy traffic to continue in the northbound lanes Monday, though he is hoping that by the afternoon, some of the congestion will be alleviated.

Update, 9 p.m. Aug. 16

Only the fast lane on the northbound side of the Cuesta Grade is open. All three southbound lanes are open.

Northbound traffic is currently backed up to Monterey Street in San Luis Obispo.

Whitney Nicole, a driver waiting in traffic on the Grade, said she has moved three to four miles in 40 minutes.

According to Cal Fire, firefighters are doing "direct attack strategies," and winds are calm.

Update, 8:20 p.m. Aug. 16

Two of the three fires — the most northern fire and the center fire — have burned together, Cal Fire said.

Firefighters are concentrating on keeping the fire west of Mount Lowe Road, and ground crews are working multiple spots over the road.

Cal Fire is currently making final air-attack drops before nightfall.

Update, 7:50 p.m: Aug. 16

The fires total 40 acres and threatens one structure, according to Cal Fire. Northbound traffic is backed up half way up the Grade.

Original story: Aug. 16

Three separate fires are burning on the Cuesta Grade, with each fire ranging from 3 to 6 acres, according to a Cal Fire spokeswoman.

According to the CHP traffic log, the fires were caused by a Ford pickup that was dragging a chain.

Ten fire engines, four aircrafts and two dozers are among the response vehicles that have been assigned to the fires.

According to the CHP traffic log, the fires began around 6:10 p.m. Sunday evening.

Multiple lanes on Highway 101 are closed as firefighters work to contain the blazes.

This story was originally published August 21, 2015 at 7:19 PM with the headline "Photo of vehicle that may have started Cuesta Fire is released."