The horrifying L.A. wildfires are being fueled by the worst conditions January has ever seen

Southern California is facing a rare and dangerous juxtaposition of extreme winds and mid-winter drought on Tuesday and Wednesday, a worrying example of the state’s expanding wildfire threat as climate change worsens.

At least 10 new fires had started across Los Angeles County as of Tuesday afternoon, even before the strongest winds were expected to arrive.

The Palisades fire—the largest of them, with ominously billowing towers of smoke visible across most of Los Angeles—began as a brush fire in the Hollywood Hills on Tuesday morning and quickly grew to more than 700 acres, prompting mandatory evacuations—including of celebrities.

The City of Los Angeles warned of a “destructive, widespread, and potentially life-threatening windstorm” and the National Weather Service called the combination of strong winds and dry conditions a “particularly dangerous situation.” One California-based meteorologist said on social media that it was the most scared he’s ever been putting a forecast together.

This week’s windstorm has the potential to be particularly widespread and long-lasting. The notorious Santa Ana winds could get as high as 100 mph early Wednesday in parts of the foothills surrounding Los Angeles. That would make it the strongest and potentially most destructive Southern California wind storm since November 2011. In a worst-case scenario, dozens of wildfires could pop up simultaneously and rapidly grow out of control—overtaking neighborhoods and cutting off evacuation routes much more quickly than firefighters can react to slow them down.

People are running from their cars. Omg. Standstill traffic out. Fire is all around us. pic.twitter.com/OsBmBOKlmp

The National Weather Service defines “extremely critical” fire weather as sustained winds in excess of 30 mph and relative humidity of less than 10% in the presence of drought conditions and temperatures warmer than 70 degrees. This is the first time in history these criteria have been met anywhere in the United States during the month of January.

In preparation, Southern California Edison told more than 400,000 households—about 15% of homes and businesses across the region—to prepare for pre-emptive power outages. Cal Fire moved equipment from Northern California to Southern California on Monday in advance.

The planned electricity outages are “a tool of last resort” to prevent the grid from sparking wildfires due to downed power lines. Utilities have increasingly used them to limit their own liability. PG&E, the state’s largest utility, filed for bankruptcy in 2019 after accruing hundreds of millions of dollars of civil settlements and criminal penalties from catastrophic wildfires sparked by their equipment.

Santa Ana winds form when cold, dense desert air is channeled through narrow canyons and down the mountains towards the coast. Recent studies have found that Santa Ana wind events could get less frequent, but perhaps more intense in the winter months due to climate change.

The downsloping winds will act as a blow dryer for already parched vegetation, helping small embers quickly grow to towering flames and mature wildfires leapfrog over containment lines.

While some parts of Northern California have seen twice the typical amount of rain and snowfall this winter, there has been essentially no precipitation for the past nine months in the southern part of the state. As a result, severe and even extreme drought have reemerged in California in recent weeks.

Santa Ana winds are most common during the winter months, but it’s exceedingly unusual for them to occur at the same time as a pre-existing drought—the winter months typically mark the peak of the rainy season across the West Coast.

As winters warm and California dries out, extreme Santa Ana windstorms will overlap with drought conditions more frequently. A majority of the largest, deadliest, and most destructive wildfires in state history have all occurred within the past 10 years. The emergence of extreme wintertime wildfires in California are one of those classic “this is climate change” moments: A specific set of weather conditions are now occurring in such a way to produce the potential for rare disasters to become much more common.