Hot Air

A seasonal feature, alien to Easterners, is the winter onset of Santa Ana winds. Hot air in December — it reinforces the strangeness of Los Angeles. The Santa Anas have become threads in the city’s dystopian lore, and that from the hands of writers like Joan Didion and Raymond Chandler, not the hacks.

But dry, hot air during L.A.’s winter isn’t freakish. You could say the lay of the land has a lot to do with it — topography. Another smart writer, John McPhee, described it. The air comes from the broad Great Basin, east of the Sierras in Nevada and Utah. Those areas, at higher altitude, are usually cooler in winter than is the L.A. region. But when clockwise winds push west to the coast, the air is compressed and heated as it drops in elevation on its way to the sea-level expanse of Los Angeles.

The Santa Anas are a withering breeze. L.A.’s humidity, which is usually — and thankfully — constrained, plunges. It’s as if the wind strangles all water vapor out of the air, as if one’s lungs are lined with a woolen sweater. Even David L. Ulin, former book editor of the Los Angeles Times (whose feature story on “Slow Time” appears in this issue), once wrote, “I detest the Santa Ana; it is my least favorite aspect of the Southern California life.” He was born in New York.

The wind from the east is a fire wind, a foehn, as McPhee explained. But in the desert, fire, like water, associates with birth. Plants dry out, says Philippa Drennan, LMU professor of biology, becoming fodder for fire. Some plants need fire to germinate and grow. “Fires bring about new flowering and growth.” Swaths of flowers appear like “little carpets,” she says.

Inevitably, the Santa Anas blast their way to the ocean. But there they contribute to upwelling, says John Dorsey, LMU professor of civil engineering and environmental science. The winds churn up nutrient-rich waters from the depths. It’s a boon to biological productivity, he says, and a surfer’s delight: “The wind blows straight to the waves, grooms them beautifully, and if it’s a strong enough wind, you get beautiful veils coming off the waves.”

If the Santa Anas are L.A.’s season of overheated winds, then the nation has had its taste of uncomfortable hot air for the past 18 months. But now pollution, for a while at least, is driven off, and we can see in pristine sunlight, assess the damage and even hope for signs of new life.

Joseph Wakelee-Lynch is editor LMU Magazine. He is also host of “Off Press,” the podcast of LMU Magazine. You can find other writings of his at his Editor’s Blog. Follow him on Twitter @jwlmageditor.