Hot temperatures. Strong winds. Bone-dry vegetation.
Fire experts and climatologists described eerie similarities between the Carr Fire burning in Shasta County and the deadly North Bay wildfires that tore through much of Sonoma County last October, killing 44 people and destroying whole neighborhoods in Santa Rosa.
In both firestorms, higher-than-normal temperatures combined with strong winds made the wildfires behave more erratically, and near-record dry vegetation allowed them to spread more rapidly, taking lives, consuming homes and destroying large swaths of forestland, California Department of Forestry and Fire Protection officials said.
“In many regards, they are similar,” said Greg Bertelli, a division chief with Cal Fire who is serving as an incident commander for the Carr Fire and had performed a similar duty during last year’s North Bay fires. “There’s the dead fuels component and the fire being driven by the winds.”
The North Bay wildfires spread quickly due to 60 mile-an-hour overnight winds that made the inferno more deadly.
The Carr Fire is dangerous for a different reason.
It is burning with much lower wind speeds of 10 to 30 miles per hour, weather experts said. During the height of the fire Thursday, the fire was so hot it created its own weather system the size of about two football fields surrounding it, driving up higher wind gusts and pushing it unexpectedly in three different directions — a phenomenon referred to as a “firenado.”
“It looks an awful lot like a tornado,” said Daniel Swain, a climate scientist with UCLA. “There is a significant difference between mechanisms that drove these fires. We did not have these strong dry winds in Redding last night like we did have in Santa Rosa.”
Instead, Swain said, “the fire created its own wind… These fire-induced winds were very strong and unpredictable and drove this fire from dry brush and trees into urban areas.”
It sent large, fiery chunks of debris into the air, landing on homes, boats and forestland — advancing its spread.
In Santa Rosa last year, the reason the fires were “really bad is because there were strong winds all over the place,” Swain said. There, the Tubbs Fire grew more destructive and deadly after it jumped Highway 101 in the early morning Oct. 9, a day after the fire broke out. The fires also created swirling tornado-like conditions, Bertelli said.
The Carr Fire jumped the Sacramento River late Thursday night, forcing the evacuation of 37,000 people. Dozens of homes in residential subdivisions have been destroyed and nearly 5,000 more are threatened by flames. The tiny town of Keswick, home to about 450 people six miles northwest of Redding, was almost completely wiped out.
A Redding firefighter and a private bulldozer operator died battling the fire. It had grown to 44,450 acres by 4 p.m. Friday, destroyed 65 structures and damaged 55 others.
Cal Fire spokesman Jeff La Russo said the combination of rugged terrain in the path of the fire and extreme heat are creating challenges for firefighting crews. He said additional “fire whirls” could happen again. That could make firefighting efforts more difficult as winds pick up and the fire shifts paths.
Bertelli, the Cal Fire division chief, said though the winds aren’t as high as the fires that ripped through Santa Rosa, they could make the fires similarly destructive.
“The winds are still playing a factor as they channel down through Whiskeytown Lake,” Bertelli said. He urged residents in the path of fires to evacuate immediately when asked, to clear flammable material from around homes and during fire season “be ready, set, go.”
Last year’s North Bay fires, the Carr Fire and others burning throughout the state, including in Yosemite, are the latest sign that California can expect — and must prepare for — fires to begin earlier in the summer, officials said.
Historically, fire season has started in October, but fire-prone parts of California are beginning to see fires break out earlier in the year due in part to the warming of the climate.
“We have these long, hot, dry summers that are getting progressively drier,” Swain said. “We’re not at the end of summer yet.”