The howling rush of wind begins, sometimes in the middle of the night, thrusting abundant dust and leaves into the air. The dry conditions of fall-winter in southern California signal the inevitable Santa Anas as we know them, a shock to visitors who escape their frosty norms to this desert-like phenomenon. Tiny whirlwinds of dusty tornados spin around our neighborhoods, depositing debris that calls for days of porch sweeping and fire proofing. Yes, the threat of fires and then actual wildfires usually follow in succession and spread at lightning speed, fueled by continuing gale force winds. Then come the power outages, the fallen trees and broken street signs. It’s an all too familiar annual sight for So Cal residents.
A peek back in time to early California shows us relatable experiences and a history of studying the Santa Anas with the science behind it. The Santa Ana winds are almost a part of the south coast’s character, even mentioned in literature and movies (such as The Holiday and books by T.C. Boyle). In “Two Years Before the Mast,” Richard Henry Dana recounts a “violent northeaster” in 1836 that forced his ship, the Pilgrim, to leave its anchorage in San Pedro and seek refuge in the leeside of Santa Catalina Island. In his memoir, “Sixty Years in Southern California,” the Jewish-German Angeleno Harris Newmark recalls an 1865 windstorm that “struck Los Angeles amidships, unroofing many houses and blowing down orchards.”
Several misnomers exist about the winds, though, the first being that it’s a “desert” wind that originates in a desert location. Though actual high pressure builds over the Utah/Nevada desert in the previous months (summer through September), it then flows outward toward coastal low-pressure systems. The air is then squeezed and warmed down the Sierra mountain slopes. Once the warm air compresses through canyons (namely the Santa Ana canyon), it intensifies like water flowing through a narrower stream. This causes a dramatic drop in humidity. The resulting wind is extremely dry, hot and fast…