How will winter’s wet weather affect fire season in the East Bay?

Record rainfall last winter mitigated California’s severe drought and brought a slow start to fire season. But the wet weather hasn’t reduced the threat. 

The heavy downpours that bombarded the Bay Area and the relatively cool weather that followed kept vegetation from drying out in the spring and early summer. But as the summer wears on, that vegetation will become fuel for fires, said Ranyee Chiang, director of the Meteorology and Measurement Division at Bay Area Air Quality Management District. 

“We have a below-normal and normal wildfire potential for the last month and in July because of the rains and the cool start to the year. And then starting in August and September, those fuels will become more dry,” Chiang said during a presentation Wednesday before the BAAQMD board. “In August and September, we’re looking at going back to a normal level of risk.”

The Bay Area experienced the wettest three weeks in 161 years from late December last year into early January this year due to nine atmospheric rivers. But since April, the region has been relatively dry, with April and June seeing less rain than those months did in 2022, National Weather Service records show.

In addition, Chiang said, drying vegetation left from the previous three years of drought will pose fire potential during late summer and early fall.

California currently has three active major wildfires: Day Fire and Lincoln Fire in Riverside County in Southern California, and Whiskey Fire in Madera County in the Central Valley. The state has had 38 major fires so far this year, about half of last year’s number. Those don’t include fires covering fewer than 10 acres.

“In the warmer months, we start seeing more fires because the vegetation is drying out,” said Chelsea Burkett, spokesperson for Cal Fire’s Santa Clara unit, which includes Alameda County. “That’s oftentimes during the summer months, but that doesn’t mean that we aren’t also seeing fires throughout the entire calendar year.” 

Wildfire season varies throughout the state and is dependent on topography, vegetation growth and weather patterns, Burkett noted. Peak season in the Bay Area tends to be from late summer to early fall. 

In October 1991, a blaze that became known as the Tunnel Fire killed 25 people, injured 150 and burned 1,520 acres in the Oakland Hills. 

Currently in Alameda County, fire hazard severity is very high in the hills bordering Berkeley, along Grizzly Peak Boulevard, and through the area surrounding the San Leandro Reservoir to Lake Chabot, according to Cal Fire’s hazard severity zone map.

Fire hazard is based on physical conditions and their likelihood to create wildfires without mitigation measures. It is evaluated over a period of 30 to 50 years. Risk, on the other hand, is based on the potential damage a wildfire can cause.

BAAQMD has a number of programs to reduce wildfire risks and mitigate air quality issues. One of them is the Wildfire Prevention Chipping Pilot Program, which offers free chipping services for qualifying residents to dispose of potential fuel loads.

The agency also distributes air filters to low-income residents with respiratory conditions, and funds upgrades to HVAC systems in evacuation centers, community centers, senior centers, schools, libraries and homes.

Bay Area residents can look up wildfire safety tips, monitor air quality, get air purifier information and instructions on how to reduce wildfire smoke indoors on BAAQMD’s website.

Cal Fire also has a checklist to help residents prepare for the fire season, offering tips on how to harden homes by using fire-resistant building materials, plan for evacuation, put together an emergency kit, talk to young children about fire safety and how to escape when trapped. It also spells out how residents can create a checklist on their phones.