The Santa Ana winds have been extreme this year, and some climatologists suggest global warming might be strengthening extreme weather. But the Santa Ana winds could show a different aspect of global warming's impact.
The unseasonably strong Santa Ana winds that have pounded southern California during the past two days have left hundreds of thousands of residents without power, not to mention closed schools and businesses. Many counties are on emergency footing and even Griffith Park, one of the nation’s largest urban parks, has closed as crews struggle to clear fallen trees and debris away from power lines and off roads.
But the extreme winds – the strongest in at least a decade – have also raised the familiar question: Are they one more indication of global warming's larger trend toward extreme weather?
The answer is no. Mostly.
On one hand, most scientists agree that “the extremity and magnitude of extreme weather events has been trending upwards over the past 60 years,” says John Plavan, CEO of EarthRisk Technologies, a San Diego firm that models weather-related risks for energy clients.
Yet the same climate changes that are driving certain extreme weather events will also soften others, says David Easterling of the National Climatic Data Center, a part of the National Oceanic and Atmospheric Administration in Asheville, N.C.
The Santa Ana winds could be an example of that. The annual winds that sweep through southern California from November through April are caused by high-pressure systems sweeping cool air from the Great Basin southwest into the Los Angeles Basin. As the winds descend the San Gabriel Mountains, they heat rapidly, resulting in the hot, strong winds.