NorCal Fires Latest: Multiple Blazes Erupt Ahead Of Heat Wave

SAN FRANCISCO — Bay Area fire crews have battled a rash of fires in the days leading up to the first major heat wave of the season, and the dry spell ahead could create opportunities for new ones to ignite.

High winds over the weekend fanned the Corral Fire as flames burned across more than 14,000 acres of grassland in San Joaquin County. California's largest wildfire of the year so far spurred evacuations and destroyed one home in Tracy before calmer conditions helped fire crews boost containment to 90 percent by Tuesday morning.

On the Peninsula, powerful gusts fueled a fire that erupted Monday morning in a large apartment building under construction in North Fair Oaks. Firefighters upgraded the response to eight alarms, drawing support from neighboring cities, as nearby residents remained under mandatory evacuation orders deep into the afternoon.

In Alameda County, fire crews rushed to extinguish three grass fires that ignited Monday. In Livermore, a fire near Patterson Pass quickly charred nearly 100 acres Monday afternoon. Firefighters were able to get a handle on the blaze before it damaged any structures or powerlines and reported 90 percent containment Tuesday morning.

Another grass fire ignited in Livermore shortly after 5:30 p.m., burning up to 15 acres and downing powerlines along Cross Road. Around the same time, Alameda County firefighters tamped out another grass fire burning along Sydney Way in Castro Valley.

NorCal fire agencies are urging caution as a dry heat climbs into the 90s and beyond for inland communities over the next few days. As KQED reports, despite another robust winter that helped alleviate drought conditions across the state, the risk for grass fires like those seen recently has grown.

"We've had two wet winters, which helps our bigger fuels, our brush and our timber, soak up that rain, which makes them less susceptible to burning," Josh Silveira, a Cal Fire battalion chief, told the station. "But the double-edged sword is that with a wet winter, two years in a row, we have a tremendous grass crop, very thick, very tall."

Meteorologists at AccuWeather echoed the concern, pointing to the Corral Fire as a prime example of what can happen when topsoil dries out and becomes "primed for ignition."

"The Corral Fire has become the first 10,000-acre fire this year," AccuWeather Meteorologist Brandon Buckingham said. "And given the heat, dryness and sunshine this week there will likely be more fires breaking out that can quickly spread."

A heat advisory will remain in place Tuesday through Thursday for much of the North Bay and East Bay, including portions of Napa, Sonoma, Contra Costa and Alameda counties. The advisory will expand Wednesday to cover parts of Santa Clara, San Benito and eastern Monterey counties.

According to the National Weather Service, temperatures could reach 100 in Cloverdale by Wednesday afternoon, with Concord and Livermore coming within a couple of degrees. Afternoon highs will generally run 10 to 15 degrees above their seasonal normals for inland areas, presenting a moderate risk of heat-related health impacts.

To the east, the Central Valley will be under an excessive heat warning with major heat-related health risks for those without access to adequate cooling during the hottest parts of the day.

While the forecast calls for calmer winds after a few gusts Tuesday, the weather service warns fire hazards will remain a concern.

"Warm to hot daytime highs, above to well-above June normal highs — hottest inland with 90s to lower 100s, nearer the coast 80s and 90s, and 70s/80s at the beaches," NWS Bay Area cautioned Tuesday. "Hot weather will result in elevated fire weather conditions at least through Thursday."

Forecasters warned those looking to beat the heat at the beach will also need to be careful, with breaking waves as high as 20 feet and dangerous sneaker waves expected Wednesday and Thursday.