After a relatively mild summer and a temperate start to fall, the perils of potentially hazardous fire conditions will return to the Bay Area this weekend.
On Saturday and Sunday — with wind gusts that the National Weather Service anticipates to be at least 50 mph driving an air mass that’s drier than usual over vegetation still overgrown from last winter’s rain — fire danger is front and center again.
The weather service early Friday issued a red flag warning for the Santa Clara Hills, East Bay Hills, Santa Cruz Mountains, Marin Coastal Range and the North Bay Interior Mountains. It will remain in effect through the weekend.
“Simply put,” NWS meteorologist Matt Mehle said, “this is a big giant heads-up.”
Among the chief concerns, according to the weather service, will be the ability of any small spark to start a blaze and spread quickly. Trees and power lines also could suffer damage in the winds, the agency said.
According to PG&E spokesperson Tamar Sarkissian, the utility was not anticipating the need to shut down power as part of the safety efforts but that it was monitoring the weather.
The threat of fire may have seemed to recede into the background over the summer because the weather in general was more mild and the conditions for sparking a blaze less dangerous, fire officials said. In truth, they said, the elements needed for an out-of-control wild fire always were there.
“Our fire season hasn’t been over,” Contra Costa Fire Protection spokesperson Capt. Chris Toler said. “It’s just delayed.”
An uptick in fire conditions is not uncommon for the region, especially in late October, he said.
“We’re getting to the point where the October winds are starting to hit,” Toler said. “We haven’t had any major vegetation fires over the past few months, and what that means is that there’s more fuel to burn in weather conditions like we have this weekend. There is a lot more fuel, because a lot of vegetation has not burned.”
The dangerous conditions are the result of an extremely dry air mass that’s moving through the region from the north. The offshore winds that are such a regular part of the Bay Area weather pattern will remain, Mehle said. He added that their direction in this pattern will lead them to go down the slope of mountain ranges, further speeding up the evaporation of moisture.
“If you were to compare this air mass to other air masses we get, this one would be much drier,” he said. “It’s a colder source that’s sending it. It has a cold path, and that tends to dry out the air.”
Also, the winds may prove to be far more powerful than early estimates.
“I wouldn’t be surprised to see gusts get up to 60, maybe 70 mph in the highest spots, especially in the East Bay and North Bay mountains,” Mehle said.
All of this will come amid mild temperatures that are expected to peak at 74 degrees and clear skies that might suggest it’s a good night to get out the grill. Ignore the urge, officials said.
“Avoid barbecuing, don’t use fire pits, limit all that stuff,” Toler said. “Mow your lawns Friday. If you don’t do it Friday, wait until Monday.”
By Monday, the winds will be gone, air with a bit more humidity will be back and “it will be a return to normal,” Mehle said.
This is a developing report. Please check back for updates.