Weather Watch

It’s getting hotter and hotter, and that’s not good news for California fire season

An outbuilding burns at Camp Whittier during the Whittier Fire in the Santa Ynez Valley.
An outbuilding burns at Camp Whittier during the Whittier Fire in the Santa Ynez Valley.

It seems like every day lately brings mushroom-like pyrocumulus clouds that tower over the Central Coast from wildfires in the inland areas.

San Luis Obispo and Santa Barbara counties have seen well above typical July temperatures away from the coastline. The normal high temperature for Paso Robles for July is 93 degrees. But halfway into this month, the average high temperature is already at 98 degrees, and that number may reach over 100 degrees by the end of next week.

In other words, July could be the warmest on record for many of our inland areas. To make matters worse, the Climate Prediction Center forecasts above normal temperatures through September. The higher temperatures lower vegetation moisture levels, which means that fires can burn more quickly and start more easily.

Last year’s rain season (July 1, 2016 through June 30, 2017) delivered above average precipitation for most Central Coast locations, which in turn created huge amounts of grass and other seasonal vegetation. This vegetation is interwoven with large amounts of dead fuel from the multi‐year California drought.

All of these ingredients are coming together like a perfect storm to produce a fierce fire season.

Unfortunately, wildfires are likely to get worse in the future. As any firefighter will tell you, three ingredients are needed to have a fire: oxygen, heat, and fuel. It’s called the ”fire triangle.” A heat source, such as a spark from a trailer chain hitting the highway, can cause a fire to ignite. But the heat also preheats the fuel in the fire’s path, allowing it to spread.

Warm temperatures and stronger than normal winds not only help to dry vegetation through evaporation but also provide plenty of oxygen for combustion.

Overall, warmer temperatures, cumulative winds and abundant fuel have fed into a dreadful feedback loop. Average yearly temperatures are forecast to rise by six degrees by the end of this century. Locally, temperature records keep falling like bowling pins.

Not only will the atmosphere get warmer, but droughts may become longer. Average temperatures in the Arctic have increased at about two to three times faster relative to the midlatitudes. This is referred to as Arctic Amplification. Many climatologists and scientists suspect this condition may have been behind the big and persistent ridge of high pressure that produced the recent California drought. However, a warmer atmosphere can hold a greater amount of water vapor with the potential of more intense rainfall events.

According to Cal Fire, a 300 percent increase in wildfire risk in non-urban areas of California is predicted by 2050 due to climate change.

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To assist Cal Fire and municipal fire departments, PG&E has begun daily aerial fire patrols across Northern and Central California, including the Central Coast, seven days a week. These crews primarily fly during the afternoon hours when wildfires are most likely to ignite.

In addition to its daily aerial fire patrols, PG&E is removing dead or dying trees that could fall into lines and spark a fire. The company is also pretreating utility poles with fire retardant to protect them from flames and prevent them from becoming road debris that could block firefighters from reaching fires.

The PG&E Meteorology Services department is using high-resolution weather forecast data from the PG&E Operational Mesoscale Modeling System, along with the National Fire Danger Rating System, to produce daily fire danger ratings for the PG&E service area, which encompasses most of Northern and Central California. PG&E also provides funding to Fire Safe Council’s fuel-reduction projects in numerous counties.

“Wildfires continue to be a huge risk along the Central Coast” said Pat Mullen, PG&E’s local division director. “PG&E is proud to help our customers prevent wildfires in the area and protect critical infrastructure. We live and work in this community, and there’s nothing more important to us than the safety of local residents.”

John Lindsey’s column is special to The Tribune. He is PG&E’s Diablo Canyon marine meteorologist and a media relations representative. Email him at or follow him on Twitter @PGE_John.