‘Dice was really loaded’ for California wildfires

High winds, dry weather created explosive situation

McClatchy Newspapers

WASHINGTON — A cascade of extreme weather events fed Northern California’s wildfires that exploded last Sunday: Unusually high winds blew flames through unusually dense and dry vegetation, which sprung up following last winter’s heavy rains and then were toasted by months of record hot temperatures.

“The dice was really loaded because of the big wet winter,” said Park Williams, a California native and a research scientist at the Lamont-Doherty Earth Observatory at Columbia University. “That set up the West with a lot of fuel to burn, and this summer has been exceptional in terms of dryness.”

Scientists such as Mr. Williams say California is especially prone to wildfires, in part because of the state’s dense population, which makes it easy for sparks to be ignited and turn into raging fire storms.

“By the end of the summer and into early fall, the state’s vegetation is tinder dry,” said Jan Null, a California meteorologist and owner of Golden Gate Weather.

Then in the fall, the weather pattern flips to generate hot, dry winds that blast across the already-parched landscape. “The bottom line is that culmination of these patterns makes October a particularly tragic month for wildfires in California,” Mr. Null said.

But the recent blazes also show the fingerprints of climate change, Mr. Williams said, a harbinger of what the West should expect in the years to come.

“The fingerprint is definitely there,” said Mr. Williams, who last year contributed to a study on climate change’s impact on western wildfires. “The connection between temperatures and fire is one we see again and again in the correlation analyses we do.”

California’s fire chief said he and other firefighters were stunned by the fury and speed of the blazes that erupted last Sunday night. “We’ve raised the bar again in California just in terms of the conditions that we’re facing and the destruction and devastation,” California Fire Chief Ken Pimlott said Monday.

As of Friday, at least 31 people had died and more than 1,500 homes were destroyed in the multiple fires, including one that destroyed much of northeast Santa Rosa, a city of 175,000 people. There, the Tubbs fire incinerated hotels, a high school, a mobile home park and vast neighborhoods, the worst oneday wildfire destruction in California since the Oakland Hills fire of 1991.

Meteorologists term the winds that struck Northern California last Sunday as “Diablo winds,” similar to the Santa Ana’s that contribute to large wildfires in Southern California nearly every fall.

In both situations, inland high pressure combined with offshore low pressure draws dry winds in from the northeast. As these winds race down the slopes of the Sierra Nevada, they compress and become warmer and stronger.

Last Sunday night, winds reached 50 mph near Santa Rosa, with some gusts topping 70 mph, according to the National Weather Service.