On Tuesday, Santa Claus Ana winds swept seaward across Southern California, scattering embers and then fanning the flames of a growing wildfire. Overnight, residents received urgent text alerts warning of potential wind gusts of up to 100 miles per hour – a terrifying escalation that turned a tenuous situation into a full-fledged crisis. As the wind howled, more embers were thrown into the air, sparking recent fires in parched, brittle brush that had not received any significant rainfall in more than eight months.
Los Angeles County, hit by drought-like conditions, was a coal bin waiting for a spark. Firefighters faced an uphill battle against winds so sturdy that planes dropping water and flame retardants were grounded. In a Wednesday morning press release, authorities warned that “all Los Angeles County residents are in danger.” Since then, evacuation orders have displaced tens of thousands of residents, and thousands more are awaiting updates. As of Wednesday evening, three major fires had consumed more than 13,000 acres, and efforts to contain them were 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, as of writing of this text 0 percent have been contained and have already become the most destructive in California’s history.
Due to extremely parched and windy conditions, the fires quickly became disastrous: “Any little spark, whether from a lightning strike, from a person, from a campfire, escalates quickly,” says Jennifer Marlon, a researcher and lecturer at Yale School of the Environment and the Yale Program on the Climate Change Communication. “When a fire breaks out in these conditions, it’s very, very difficult to contain it,” adds Kaitlyn Trudeau, senior research fellow in climate science at the nonprofit Climate Central.
Santa Ana wind events are not uncommon. “We see it this time every year,” says Jason Moreland, senior meteorologist at emergency communications platform AlertMedia. Downdraft winds coming from inland are caused by a parched high pressure system blowing from the northwest and a low, damp pressure system from the south. “It’s like having a hose and folding it in half to cut off the water. If you put a hole in the side, you have a lot of pressure to get out,” Trudeau explains. “Basically the same thing happens with air.”
However, these winds are much stronger than usual due to a decline in the jet stream near the Baja Peninsula in northwestern Mexico, Moreland explains. Winds that normally move to higher elevations reach lower areas of the terrain. “Wind phenomena of this scale occur every few decades,” he says.
Although this wind phenomenon seems extreme, Noah Diffenbaugh, professor and senior research fellow at Stanford University Woods Institute of the Environmentexplained that this may simply be due to natural weather variability and further research is needed to find out if it is due to climate change.
However, while the winds are not unusual, the climate changes increases the risk delayed and early season wildfires in California. “Not only is it a particularly strong wind, but it’s also an exceptionally dry time of year in early January,” Diffenbaugh says. Southern California’s rainy season, which runs from October to April, saw record low rainfall following some of the driest on record. Like rainfall more variable due to climate changethe overlap between the windy and parched seasons increases. “We are seeing significantly more hot, dry and windy days, especially in Southern California,” Trudeau says.