Devastating wildfires continued to burn throughout the Los Angeles metro area on Friday, extending mandatory evacuations and school closures across the region. Next week promises little chance of relief; conditions will remain favorable for both the growth of existing wildfires and for new blazes to spark, as gusty winds persist amid unusually dry conditions.
Officials reported five major blazes across the Los Angeles area as of Friday morning. The Palisades Fire in Pacific Palisades and Malibu has consumed more than 20,000 acres, while the Eaton Fire in Altadena has grown to more than 10,000 acres. At least 10,000 structures are thought to have been destroyed across Los Angeles, and 10 people have been killed.
Favorable fire weather requires dry vegetation, low humidity, and stiff winds. The combination of these ingredients allows fires to easily spark and rapidly spread; it was this dangerous mix that allowed the Palisades Fire and Eaton Fire to expand beyond any crew’s ability to control them earlier in the week.
Fire crews have since managed to start controlling the fires, helped by out-of-state reinforcements, the water in hydrants being replenished, and wind speeds dropping. (As well as helping the fires spread rapidly, the high seasonal Santa Ana winds earlier in the week at times prevented firefighting aircraft from working to control the blazes with water and fire-retardant chemicals.) The bad news is that those winds may now be about to pick up again—and that on all other fronts, conditions aren’t likely to be in firefighters’ favor anytime soon.
What Happens Next With the Weather
The Storm Prediction Center, the agency of the National Weather Service tasked with issuing fire weather outlooks, says that the risk for fire conditions will remain elevated across Los Angeles heading into this weekend.
We could see two more moderate Santa Ana wind events in the coming days—one early in the day on Sunday, and another possibly on Tuesday. These gusts could encourage the spread of existing fires and the ignition of additional blazes.
A Santa Ana wind event occurs when there’s a pressure difference between the Great Basin—the vast stretch of land in Nevada and Utah—and coastal communities around Los Angeles.
Meteorologists often use the air pressure differential between Las Vegas and Los Angeles to predict these winds. A stronger pressure difference creates stronger winds that rush toward the coast, which feeds existing wildfires. This is what they are predicting we could see again in the coming days.
Vegetation will also continue to be exceptionally dry across the region. It’s the middle of southern California’s rainy season right now—yet the rain is nowhere to be found. After seeing its third-wettest February on record last year, Los Angeles International Airport has reported only 0.03 inches of rain since the start of last summer.
Despite the middle of January being prime time for Los Angeles’ rainy season, there’s very little hope for meaningful rain over the next week and a half. NOAA’s Climate Prediction Center announced Thursday that we’ve officially entered La Niña, a pattern of colder-than-normal water temperatures in the Pacific Ocean around the equator. Changes in the atmosphere responding to La Niña can force the jet stream to move northward over the Eastern Pacific Ocean, which shunts storms into Canada’s West Coast instead of the western US, starving states like California of rain.
Right on cue, the predominant storm track across the Pacific Ocean will remain up near the Gulf of Alaska through the middle of January, providing few opportunities for rain to make it as far south as Southern California.
Forecasters expect a weak La Niña to stick around through the end of winter, with decent odds that the pattern will fade in time for spring. Unfortunately, this timing could coincide with the onset of Southern California’s dry season.
That’s not to say we may not see opportunities for rain in the coming months. However, little to no rain through at least the middle of January will keep vegetation exceptionally dry throughout the region. The ongoing risk for new fires and additional fire growth will hinge on bouts of low humidity with gusty winds—and any additional Santa Ana wind events could prove dangerous in the coming weeks.