A woman was killed in a weather-related car crash Wednesday afternoon as heavy rainfall continued to pour down across San Luis Obispo County, causing minor flooding in the South County and rock slides on the North Coast.
Meanwhile, the National Weather Service expanded its flash flood watch to include all of San Luis Obispo County on Wednesday afternoon, with the heaviest rain still on the way overnight. The flash flood watch will be in effect until 5 p.m. Thursday.
"Flash flooding and mud and debris flows are likely in and around recent burn areas in the watch area," the NWS said. In San Luis Obispo County, "the heaviest rainfall intensities are expected later tonight into Thursday morning."
"Highway 1 north of Morro Bay especially at risk for flooding with rock/mudslides," the NWS tweeted.
The peak of the storm is predicted to arrive at 4 a.m. Thursday, when rainfall rates are expected to reach 1 inch per hour, according to PG&E meteorologist John Lindsey.
By 6 p.m. Wednesday, most San Luis Obispo County locations had recorded between 1 and 2 inches of rain over the previous 24 hours, according to slocountywater.com.
Rocky Butte recorded the highest total at 4.18 inches. Elsewhere around the county, San Luis Obispo received 1.42 inches, Arroyo Grande received 1.31 inches and and Nipomo received 1.65 inches. In the North County, 1.30 inches fell in Templeton and 0.87 fell in Atascadero.
Lindsey said there is a chance of thunderstorms into Thursday, with strong to gale-force (25 to 38 mph) northwesterly winds.
By 4 p.m. Thursday, the rain is expected to taper off. A break in the rain is expected Friday and showers are forecast for Saturday and Sunday, Lindsey said.
On Highway 41, a woman, believed to be 19, was reportedly driving a maroon Isuzu Rodeo on Highway 41 west of Atascadero about 12:45 p.m. when she lost control of the vehicle, according to California Highway Patrol spokesman Jordan Richards.
Richards said the woman was traveling at a high rate of speed and was not wearing a seat belt when the vehicle lost traction and veered down an embankment about 10 feet off the road, Richards said.
The driver's side of the vehicle struck a tree, then tumbled 25 to 30 feet down the embankment, Richards said. The woman was partially ejected and pronounced dead at the scene.
"This is a terrible reminder that, in this type of weather, you have to slow down," Richards said. "You don't always have to go the speed limit. It is OK to go slower than the posted speed limit."
California Highway Patrol responded to numerous other vehicle crashes around the county Wednesday, though no other fatalities were reported as of 6 p.m.
North Coast rock slides
Near Cambria, San Luis Obispo County workers cleared a rock slide that blocked Santa Rosa Creek Road about four miles east of Coast Union High School on Wednesday afternoon — despite continuing rain and other rocks and soggy soil looming overhead.
The slide completely covered the rural road, and an excavator was brought in to shovel dirt and debris into waiting dump trucks.
Farther north, Highway 1 was closed just north of Ragged Point Inn because of rock slides.
Travelers were still able to access the inn from the south. Traffic can go as far north as Ragged Point, but no farther, according to the California Highway Patrol.
Caltrans officials planned to “assess the situation Thursday morning,” spokesman Jim Shivers said.
“It’s not a large event, but we are seeing a continual stream of rocks” coming down. “We hope to have things cleared” by sometime Friday morning, Shivers said Wednesday morning.
South County flooding
Several areas in South County saw flooding on roadways Wednesday as the rain soaked low-lying communities.
The CHP declared a hard closure of Highway 1 at 13th Street in Oceano at about 8:35 a.m. The road was reopened around 12:15 p.m. Then it was closed again at 6 p.m.
In Avila Beach, workers tackled a flooded First Street intersection at about 4 p.m., working to pump the water away. The flooding there was between 1 and 3 inches deep, and the one-block portion of the road was closed to vehicles while crews worked.
More flooding could be on the way for South County.
Ray Dienzo, technical unit supervisor for San Luis Obispo County Public Works, said Arroyo Grande Creek would likely reach "full storm" stage overnight.
The water level there reached a peak of about 25 feet on Wednesday according to Public Works. Full storm stage, or the level at which county personnel are notified to closely monitor the stream, is 27 feet.
Dienzo said the low-lying area, including a large portion of Oceano, would flood if the water reached 30 feet.
Santa Barbara County
In Santa Barbara County, rainfall rates from the powerful storm have been lower than predicted thus far, with relatively minor flooding and related problems reported.
But weather forecasters and emergency officials stressed that the the multi-day storm — fueled by a very wet “atmospheric river” of sub-tropical moisture coming in from the Pacific Ocean — could still pack a dangerous punch before it moves out of the area.
"We are referring to this moment as 'halftime' for this storm because the area is seeing a slight lull, but we have to be ready for the next, much-stronger part of this storm," said Rob Lewin, director of the Santa Barbara County Office of Emergency Management.
The National Weather Service had predicted rainfall rates overnight Tuesday into Wednesday of a 1/2-inch per hour, the threshold for debris flows coming out of the recent wildfire burn areas.
However, most areas experienced only about 1/3-inch per hour, and no debris flows had been reported as of 6 p.m. Wednesday
Evacuation orders remained in effect for some 21,000 people living in communities below the burn areas in Santa Barbara County, and were expected to remain in effect until Friday morning.
Tribune staff writers Lindsey Holden, Gabby Ferreira, Kaytlyn Leslie and Kathe Tanner contributed to this report. Noozhawk.com also contributed to this report.