California fire season likely to last through December
LOS ANGELES — The sun was beginning to set on Halloween when a small fire began to glow on a hillside near Santa Paula. Within seconds — fanned by the most potent Santa Ana winds of the season — the blaze roared to life with immense speed, chewing through thousands of acres of bone-dry brush and eventually consuming homes.
Devastating fire weather that ushered in a flurry of blazes across the state last month helped the Maria fire, which charred nearly 10,000 acres in four days, earn the title of this year’s largest Southern California wildfire. However, experts caution the blaze may be a preview of what could be a long season of devastating fires amid gusty winds and dry conditions.
A report from the National Interagency Fire Center, released Friday, predicts a higher-than-normal chance for other large fires in Southern California through December, with a late start to the rainy season looking increasingly likely. In the northern part of the state, a weather pattern that “favors offshore winds occurring over fuel beds that are primed for burning” is also expected to lead to abnormally large fires through November, according to the report.
“This may be a long fall and winter across California for both the firefighting community and the general public in terms of coping with the threats of fires,” the report states. “The best thing citizens can do is to be fire wise. Now is the time to prepare for wildfires and to have a plan to be ready for wildfires if they arrive in your area.”
Predicting how severe the fire season could be in California comes down in large part to a race between the start of the rainy season and the Santa Ana winds: which one dominates and at what time of the year, said Bill Patzert, a retired climatologist for NASA’s Jet Propulsion Laboratory.
A good soaking across the state would dampen the fire season considerably, even amid strong wind events, he said. However, Southern California hasn’t had significant rain in seven months, and meteorologists say there’s no clear sign of rain anywhere in the forecast through at least mid-November.
While October and November are not the state’s rainiest months, they’re especially important because when rains hit then, they reduce the fire risk from strong, dry Santa Ana and Diablo winds coming from Nevada and Utah toward the Pacific Ocean. Typically, October sees about six days of Santa Ana wind conditions, while November sees nine and December and January have 10 and 11, respectively. Diablo winds occur most frequently in October.
“The fire danger hasn’t diminished at all. In some ways, this is really the start of the beginning,” Patzert said. “Everything is pointing to more large fires here unless we get some rain.”
Last month’s severe winds also ushered in extremely dry air, leaving much of the state’s vegetation at near-critical dry levels. Several regions — including the southern Sierra Nevada, the San Francisco Bay Area, the Sacramento Valley and a sizable swath of the Southern California coast — have reached severely dry levels. Those parched fuels can help turn a spark into a raging inferno. Combined with strong winds, they can cast embers miles ahead of the body of large blazes, setting spot fires or engulfing homes and overwhelming firefighters.
“Californians think we are out of a drought, and we are, water-storage wise,” said Mike Mohler, deputy director of the California Department of Forestry and Fire Protection, or Cal Fire. “But after years of persistent dry conditions, those dead fuels are still scattered across the landscape. And it only takes a 12-hour Santa Ana wind event to bring live fuels to critically dry levels.”