Three large wildfires—driven by ferocious Santa Ana winds—are tearing through Southern California, forcing tens of thousands to flee and shrouding Los Angeles in smoke.
The Palisades, Eaton, and Hurst fires covered more than 5,600 acres of Southern California as of Wednesday morning. Tens of thousands were under mandatory evacuation orders but the fires increased in size overnight, helped by the blustery Santa Ana winds.
ESA’s Copernicus Sentinel-2 mission captured the above image of the Palisades fire at 10:36 a.m. local time on January 7. Since then—just 24 hours ago—the fire has exploded in size alongside the two aforementioned blazes. Officials warn that the fires are continuing to rapidly spread, in no small part due to a rip-roaring wind event out of the east.
Santa Ana winds and an ‘atmospheric blow-dryer’
Santa Ana winds are east- or north-easterly winds that blow towards the Pacific coast. The winds can happen a number of times during the year, but when paired with dry (low humidity) conditions, the gusts can metastasize fires that that would otherwise be more easily handled.
As of Wednesday morning, the National Weather Service had a red flag warning for wildfires in place in Los Angeles through 4:00 p.m. Pacific Time, an air quality alert in effect through 5 p.m., and a high wind warning in place through 6 p.m.
“The atmospheric blow dryer is really going to dry things out even further, and because this is going to last several days, the vegetation will become progressively dryer the longer the wind event goes on,” said Daniel Swain, a climate scientist at the University of California, Los Angeles, in a university release. “So some of the strongest winds will be at the beginning of the event, but some of the driest vegetation will actually come at the end, and so the reality is that there’s going to be a very long period of high fire risk.”
A perfect storm: parched vegetation, low humidity, gusty winds
Conditions on the ground—namely, extremely dry vegetation—have primed the area for wildfire spread. But the real catalyst for the speed and unpredictable nature of the blazes are fast-moving winds. According to NWS, the north winds are generally 30 to 40 miles per hour (48 kilometers per hour to 64 km/h) with gusts up to 60 mph (97 km/h). The most powerful Santa Ana winds can generate gusts of 100 mph (160 km/h); and indeed, officials recorded one 100 mph gust in the San Gabriel Mountains around 5 a.m. local time Wednesday, according to the NWS.
“Today’s life-threatening windstorm shows just how quickly extraordinarily dangerous conditions can arise. Southern California has experienced a particularly hot summer, followed by almost no precipitation during what is normally our wet season,” said Alex Hall, director of UCLA’s Sustainable LA Grand Challenge, in the same release. “All of this comes on the heels of two very rainy years, which means there is plenty of fuel for potential wildfires.”
Besides pushing fires one way or another, the winds can blow down trees and power lines, providing more ways for vegetation to ignite and causing power outages in the affected areas.
“These intense winds have the potential to turn a small spark into a conflagration that eats up thousands of acres with alarming speed — a dynamic that is only intensifying with the warmer temperatures of a changing climate,” Hall added.
What the wildfires and weather might be today
Though the Palisades fire is the largest, covering around 2,900 acres, the Eaton fire swelled overnight, nearly doubling its size in a few hours as of 6 a.m. Pacific time.
The evacuation orders for the Eaton Fire expanded Wednesday morning to include the Altadena and Sierra Madre areas; NASA’s Jet Propulsion Laboratory in La Cañada Flintridge is also subject to the order, though the lab was already on a telework notice as of yesterday.
Though the winds are expected to drop off by late morning local time, they will remain strong and conditions ripe for wildfire spread will persist throughout the day.
As the National Weather Service website cautions, if you see or smell smoke it’s recommended that you stay indoors with windows and doors closed, avoid intense physical activity outside, wear an N-95 mask if you must be outside, and run your air condition and/or air purifier. That is, of course, unless the fire is at your doorstep and local authorities mandate evacuation.
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