Tuesday, Santa Ana winds swept across the ocean in Southern California, scattering embers and fanning the flames of the growing wildfire. Later that night, residents received emergency text alerts warning of gusts of up to 100 mph—a terrifying surge that turned a critical situation into a full-blown crisis. As the winds howled, more embers flew, sparking new fires in dry, brittle areas that hadn’t seen much rain in more than eight months.
Los Angeles County, plagued by drought-like conditions, was a small box waiting for a spark. Firefighters faced such an uphill battle against heavy winds that planes used to drop water and fire retardant were shut down. Officials warned at a press conference Wednesday morning that “all residents of Los Angeles County are at risk.” Evacuation orders have since displaced tens of thousands of residents, with thousands more pending revisions. As of Wednesday evening, three large fires had burned more than 13,000 acres with management efforts lagging: The Palisades Fire in Pacific Palisades and Malibu, the Hurst Fire in Sylmar, and the Eaton Fire near Pasadena showed no signs of abating, at the time of writing. 0 percent contained, and already the worst in California history.
The fires quickly turned catastrophic because of the unusually dry and windy conditions: “Any little spark, whether it’s struck by lightning or a person or a fire will grow quickly, it will grow quickly,” said Jennifer Marlon, a research scientist and professor at Yale. The School of the Environment and the Yale Program on Climate Change Communication. “Once a fire starts in these conditions, it’s very difficult to control,” added Kaitlyn Trudeau, senior climate scientist at the non-profit media organization Climate Central.
Santa Ana wind events are not uncommon. “We see it every year around this time,” said Jason Moreland, senior meteorologist at emergency communications site AlertMedia. These downward winds, which originate inland, are caused by a dry high-pressure system from the northwest, and a low-pressure, moist system from the south. “It’s like you have a pipe and you twist it to cut off the water. “If you drill a hole in the side, you have a lot of pressure to get out,” explained Trudeau. “That’s what happens in the air.”
However, these winds are stronger than normal because of the jet stream near the Baja Peninsula in northwestern Mexico, Moreland explained. Winds that are usually brought down to high altitudes reach low altitudes. He says: “Every so many decades, we get windy events like this.
Although this wind event seems extreme, Noah Diffenbaugh, a professor and senior fellow at Stanford’s Woods Institute for the Environment, explained that it may be due to natural climate change—and more research is needed to determine whether it is caused by climate change.
However, while the winds are not seasonal, climate change is increasing the risk of late or early season wildfires in California. “This is not only a high wind event, but it’s also a very dry season here in early January,” Diffenbaugh said. Southern California’s wet season, which runs from October to April, saw record low rainfall, following the wettest fall on record. As weather becomes more variable due to climate change, the overlap between windy and dry seasons is increasing. “We’re seeing a large number of long, hot, dry, windy days, especially in Southern California,” Trudeau said.