Thursday is one of the most dangerous wildfire days L.A. has ever seen
Thursday looks to be a pivotal, frightening day in Southern California’s battle against a wildfire siege that began early this week and has since spread out of control. At least three large fires are currently burning in and around Los Angeles, including one — the Thomas Fire — which has already burned at least 90,000 acres near Ventura.
Early Thursday morning, authorities closed the 101 Freeway in both directions due to strong winds pushing fire close to the road, cutting off movement between Santa Barbara and Ventura counties. Evacuation orders have gone out for idyllic communities in the Ojai Valley, as well as parts of Santa Barbara, as flames move toward the coast, according to the LA Times. More evacuations are likely on Thursday.
The weather conditions on Thursday are downright dire, with strong, damaging winds rushing through mountain passes and down hillsides toward the coast. This will create extraordinarily dry air, and make any new fires or ones that are already in progress extremely difficult, if not impossible, to control.
California’s fire history is replete with Santa Ana-driven, damaging blazes. However, the combination of factors present on Thursday — powerful winds, preexisting fires, desiccated vegetation, and also population growth — make it stand out as an especially risky day for the state.
According to news reports, more than 200,000 people have been evacuated due to the fires, and this number may climb as the winds interact with the fires to push them in new directions at a faster clip.
According to the Storm Prediction Center (SPC), which forecasts the risk of wildfires based on anticipated weather conditions, fire weather is likely to be “extremely critical” — a rare designation reserved for only the most threatening situations — in a swath of Southern California on Thursday.
These combustible conditions are going to affect about 9.5 million people, the SPC forecasts. Another 10.7 million people reside in a “critical” fire weather zone, including the city of Los Angeles. Elevated fire risk is forecast for Southern California straight through Saturday. “Large fire spread and extreme fire behavior will occur with any new/ongoing fires,” the SPC said in a forecast discussion.
The high winds may prevent aircraft, including helicopters and heavy water bombers, from doing their work, as well. This further inhibits firefighters’ ability to contain these blazes.
The National Weather Service is predicting strong winds to last all day on Thursday. The winds have already exceeded hurricane force in some high elevation areas, with gusts above 75 miles per hour.
While wildfires are a typical occurrence in Southern California each fall, when the dry, offshore Santa Ana winds blow, the current blazes are occurring later in the year than normal. In addition, conditions in the region are far drier than they normally would be.
These fires are an illustration of how short-term weather variability can interact with longer-term climate trends to create a precedent-setting, potentially deadly extreme event.
“The risk of large wildfires in coastal California typically peaks in Autumn after the long dry summers — typical of California’s Mediterranean climate — increase the flammability of the vegetation that fuels wildfires,” LeRoy Westerling, a scientist researching climate and wildfire at the University of California at Merced, said in an email.
“The overlap between the dry fuels and these warm dry wind events marks the peak fire risk for the year in coastal California,” Westerling said. “Usually, Autumn rains put an end to the fire season by wetting fuels and raising humidity, even though wind events may continue to occur.”
The problem is, Westerling noted, it hasn’t rained much in Southern California since March. The state also had its hottest summer on record, which dried out the vegetation that grew after one of its wettest winters, forming a perfect weather whiplash combo that is conducive to igniting large fires.
“Southern California has remained unusually dry through November and into December this year, extending the high fire risk fueled by the confluence of dry conditions and Autumn winds that are driving the large fires burning in coastal Southern California,” Westerling said.
While these fires cannot be directly tied to climate change, since they were most likely ignited by downed power lines or arson, they are consistent with what scientists expect to occur more frequently from a warming, drying climate in much of California.
The entire American West, in fact, is likely to see — and in many cases has already seen — an increase in the size and frequency of large wildfires.
“Climate change is increasing the variability of precipitation as well as increasing temperatures,” Westerling said. “This means that the probability of extremely large wind-driven fires in California occurring later in the year is increasing.”