Sign In or Create an Account.

By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy

Guides

Does Climate Change Make the Santa Ana Winds Worse?

The legendary winter gusts have long freaked out Angelenos.

The Santa Ana winds.
Heatmap Illustration/Getty Images, NASA Earth Observatory

“It is the season of suicide and divorce and prickly dread, wherever the wind blows,” the great Los Angeles chronicler Joan Didion once wrote of the Santa Ana winds. It also happens to be the season of wildfires. The winds “bedeviled” efforts to fight the deadly Woolsey fire in 2018 and created “dangerous conditions” when they whipped the nearly 20,000-acre Mountain fire in Ventura County this past fall. And they were blowing, too, when a spark of unknown origin ignited the now 23,000 acres of wildfire burning through the suburbs of Los Angeles.

Though steeped in mystery and superstition (writers call them the “devil winds”), the Santa Ana winds are common in Los Angeles during this time of year. (Scientists call them simply “offshore winds.”) The phenomenon is caused by winter’s cold, dry air becoming lodged in the bowl of the Great Basin, where it forms a high-pressure area. That clockwise-moving air wants to escape, and it does so by rushing down and south through the mountain passes to the low-pressure area on the coast: Los Angeles.

The wind can pick up a lot of speed — on Wednesday morning, gusts topped 100 miles per hour in the San Gabriel Mountains. It can also become drier and warmer — by as much as 50 degrees Fahrenheit — as it rushes through the passes toward the coast, which is what gives the Santa Anas their signature warmth, which so many find disquieting.

What makes the Santa Ana winds happening now unique?

For one thing, the current Santa Anas are on the upper end of the spectrum for velocity, which is part of why they have such a significant impact — and cause firefighters so much trouble. For another, there is a “rare placement of upper-level jet stream winds” giving the system a more northerly flow as opposed to the usual north-easterly orientation, Scott Capps, an atmospheric scientist and the head of Atmospheric Data Solutions, a forecasting firm, told me in an email. As a result, “many areas that are typically not impacted by Santa Ana winds were impacted.”

Does climate change affect the Santa Anas?

“Logically, it makes sense that climate change will impact the frequency and characteristics of [the Santa Anas],” Capps told me. However, “due to the complexity of the environment, we cannot blame one single factor for any extreme weather event.” The more obvious connection between the L.A. fires and climate change is the lack of precipitation during what is supposed to be the region’s wet season; some parts of southern California have received just 10% of their normal rainfall since October, making the area ripe for a fire.

Scientists used to think that inland warming would reduce the cold weather-related high pressure in the Great Basin and weaken the Santa Anas. While it does appear that so-called “cold” Santa Anas — caused by air in the Great Basin that is so cold initially that it’s still chilly when it reaches L.A., and which account for about a third of all Santa Anas — are becoming less frequent, the more traditional “warm” winds that are associated with wildfires don’t actually seem to bear out this hypothesis. Instead, they “are spread uniformly over the seven decades of record,” the authors of a 2021 study wrote.

If climate change is doing anything to warm or accelerate Santa Anas, the data would appear to suggest“an increasing potential of warmer and drier [Santa Ana winds] to dry out coastal vegetation and, particularly in anomalously dry winters, enhance the coastal wildfire season even into spring,” the authors went on.

While it’s far too soon to link the California disaster to climate change, the study’s authors now seem prescient: dry vegetation and an unusually dry winter both go far in explaining why this week’s fires are so destructive.

Yellow

You’re out of free articles.

Use code: LABORDAY to save 20%.
Subscribe to access Heatmap’s exclusive polling and expert analysis of energy, climate change, and sustainability, now just $99/year $79.20/year.
To continue reading
Create a free account or sign in to unlock more free articles.
or
Please enter an email address
By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy
Climate

Brace Yourselves for Snaptember

The Pacific Northwest fire season is about to get even worse.

Wildfire.
Heatmap Illustration/Getty Images

I turned on the heat this week for the first time since spring. Tuesday started out mild, damp, and overcast here in Seattle — the kind of weather the city still conjures in the popular imagination, even if about 50 days a year now are warmer than they used to be because of climate change. Summers here may be getting longer, but this morning felt truly like fall, and in the uninsulated shed where I do most of my writing, I briefly turned on the space heater to stave off the nip.

The same slow-moving low-pressure system responsible for the moody weather in the Puget Sound region will also go far in curbing the state’s wildfires, per Tuesday’s update to the National Wildland Significant Fire Potential Outlook. It’s almost obscenely good luck: September is historically one of the worst times of year for wildfire in the Pacific Northwest, after the summer’s high temperatures have dried out all the fuels but before the autumn rains arrive.

Keep reading...Show less
AM Briefing

China’s Solar Milestone

On California’s stalled reforms, space solar, and VPPs

Chinese solar power.
Heatmap Illustration/Getty Images

Current conditions: Tropical Storm Edouard is making landfall over Texas and Louisiana, bringing flooding as it moves inland • Already facing a southwest monsoon, or habagat, the Philippines is now staring down Tropical Storm Pilandok • Intensifying flooding in South Sudan’s Sudd, the largest wetlands in Africa, is displacing families by the droves.


THE TOP FIVE

1. New U.S. strikes on Iran spike oil prices

Oil prices surged north of $90 per barrel Tuesday as the United States exchanged fire with Iran amid the ongoing fight to control the Strait of Hormuz. West Texas Intermediate, the U.S. benchmark, rose nearly 2% to $91.74 per barrel. Europe’s Brent crude measure closed less than 2% higher at just below $97. Murban crude, the yardstick for oil out of Abu Dhabi, soared nearly 8% to over $106 per barrel. In a post on Truth Social, President Donald Trump said he was “not trying to force Iran to the bargaining table.” Rather, “I couldn’t care less if they sign a worthless, to them, agreement,” he continued. “I like our position now much better, with almost total control of the Hormuz Strait, and their economy totally collapsing.” Referring to the U.S. military as the “American terrorists,” the Tasnim News Agency, a semi-official outlet associated with Iran’s Islamic Revolutionary Guard Corps, reported that Tehran “had previously warned and promised” that “the Iranian armed forces will respond decisively and extensively to any aggression against our country’s territory and interests.”

Keep reading...Show less
Blue
Smokestacks and an American flag.
Heatmap Illustration/Getty Images

This transcript has been automatically generated.

Subscribe to “Shift Key” and find this episode on Apple Podcasts, Spotify, Amazon, or wherever you get your podcasts.

Keep reading...Show less
Yellow