‘The fuels are bone dry and ready to go,’ one meteorologist says.
They’re hurricane-like winds that transform California’s coastal hills into a hellscape when they catch a spark. And this fall, they’ve been creating a nightmarish onslaught of fires in both Northern and Southern California.
This is the third year in a row that these winds — known in the San Francisco Bay area as “Diablo winds” and as Santa Ana winds in Southern California — have fanned devastating blazes in the Golden State, raising fears that these fiery sieges are part of a new normal. Evidence continues to mount that climate change is worsening their effects.
In Northern California, this year’s windstorms have shocked forecasters because they have been so closely packed together. After being bombarded by a windstorm last Wednesday and Thursday, and a stronger “historic” blast over the weekend, the area is bracing for a third surge Tuesday and Wednesday.
Meanwhile, Southern California is bracing for its second dangerous wind storm in three days on Wednesday.
How these windstorms begin
Both the Diablo, or “devil,” winds in Northern California and Santa Ana winds to the south form during similar circumstances.
The stage is set when the jet stream, the high-altitude river of air along which weather systems track, plunges south from Alaska and Canada, and into the Mountain West.
Once low-pressure areas riding along the jet stream land in Colorado, high-pressure zones build in quickly to their north and west over northern Nevada and Utah, a region known as the Great Basin. The difference in pressure over this relatively short distance starts generating these winds.