California wildfires show no signs of slowing down

On Tuesday, Santa Ana’s winds swept seaward across Southern California, spreading embers and then fanning flames from a growing fire. Overnight, residents received urgent text alerts warning of potential 100mph gusts – a terrifying escalation that turned a precarious situation into a full-blown crisis. As the winds howled, more embers took flight, sparking new fires in dry, brittle brush that hadn’t seen significant rain in more than eight months.

Los Angeles County, plagued by drought-like conditions, was a tinderbox waiting for a spark. Firefighters faced an uphill battle against winds so severe that planes were used to drop water and flame retardants were left on the ground. Officials warned in a Wednesday morning press release that “all residents of Los Angeles County are at risk.” Evacuation orders have since displaced tens of thousands of residents, with thousands more awaiting updates. As of Wednesday night, three major fires have consumed more than 13,000 acres with containment efforts lagging: the Palisades Fire in Pacific Palisades and Malibu, the Hurst Fire in Sylmar, and the Eaton Fire near Pasadena have shown no signs of slowing down , are at the time of writing. 0 percent contained, and they have already become the most destructive in the history of California.

The fires became catastrophic so quickly because of unusually dry and windy conditions: “Any spark, whether it’s from lightning, a person or a campfire, will intensify quickly, quickly,” says Jennifer Marlon, a scientist at Yale research and teaching. School of the Environment and the Yale Program on Climate Change Communication. “Once a fire starts under these conditions, it’s very, very difficult to get it under control,” adds Kaitlyn Trudeau, senior climate science research associate at the nonprofit news organization Climate Central.

Santa Ana winds are not uncommon. “We see it every year around this time,” says Jason Moreland, senior meteorologist at emergency communications platform AlertMedia. These downslope winds, which arise inland, are caused by a dry high pressure system coming from the northwest, and a low and moist pressure system from the south. “It’s like if you have a hose and you bend it in half to get the water out. If you poke a hole in the side, you have a lot of pressure to get out,” explains Trudeau. “It’s basically what happens with the air.”

However, these winds are much stronger than usual due to a dip in the jet stream near the Baja Peninsula in northwestern Mexico, Moreland explains. Winds that are usually relegated to higher elevations reach lower terrains. “Every so many decades, we have wind events of this magnitude,” he says.

While this wind event seems extreme, Noah Diffenbaugh, professor and senior fellow at Stanford Woods Institute for the EnvironmentHe explained that it could just be due to natural climate variability – and more research is needed to find out if it is caused by climate change.

In any case, while the winds are not seasonal, climate change it increases the risk of late or early season fires in California. “This is not only a particularly strong wind, but it’s also a particularly dry season here in early January,” says Diffenbaugh. Southern California’s wet season, which runs from October to April, saw a record low rainfall, following one of the driest falls ever recorded. Like precipitation more variable due to climate changethe overlap between the windy season and the dry season is increasing. “We’re seeing a significant amount of more hot, dry, windy days, especially in Southern California,” says Trudeau.