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.

Subscribe to access Heatmap’s expert analysis of energy, climate change, and sustainability, including coverage of our regular survey research. Save $57 on an annual subscription, just $156 $99/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
A matchbook and a truck.
Heatmap Illustration/Getty Images

The United States has more roads than you could possibly imagine. Eighty-three percent of the land in the Lower 48 lies within one kilometer of a road; if you’re seeking isolation, the furthest you can get away from one is likely only about 25 miles, in a far-flung corner of Yellowstone National Park.

The Trump administration wants to build even more. Earlier this week, the U.S. Department of Agriculture filed to rescind the nearly quarter-century-old Roadless Area Conservation Rule, which protects about 45 million acres of pristine national forest lands from the construction of — and dissection by — new permanent roads. The USDA’s given reason? That new roads will provide the access forest managers and fire practitioners need to better prevent wildfires in the nation’s most remote locations.

Keep reading...Show less
Energy

Scoop: Trump to Permit Largest-Ever Gas Project in Just 7 Months

The facility will power OpenAI’s 10-gigawatt data center in Pike County, Ohio.

Donald Trump and rubber stamps.
Heatmap Illustration/Getty Images, Library of Congress

The Trump administration aims to complete its environmental review of what would be the biggest fossil fuel power project in the country in just a few months, Heatmap has learned.

This news follows Monday’s announcement from OpenAI that it intends to lease a new 10-gigawatt data center under development in Pike County, Ohio, financed by a mixture of money from a SoftBank subsidiary and the chip company Nvidia. This AI hyperscale facility — known as the PORTS-Pike project — is expected to draw power from the largest gas power facility ever built in the United States, a 9.2-gigawatt facility sited on federal lands that would be built and owned by the Energy Department.

Keep reading...Show less
Spotlight

Data Center Moratoria Are ‘Unconstitutional,’ Lawsuits Claim

A new front opens in the data center wars.

An anti-data-center sign.
Heatmap Illustration/Getty Images

A series of lawsuits filed in federal court asks a big question – are data center moratoria constitutional?

In early August, data center developer DC Blox sued the city of Nashville in federal court to overturn a zoning moratorium stopping them from building a hyperscale facility adjacent to the city zoo. “The Data Center Moratorium, moreover, is a targeted attack against DC BLOX, in violation of federal constitutional protections,” the suit argued, claiming that it defied the corporation’s due process and equal protection rights.

Keep reading...Show less
Yellow