Santa Ana winds occur when air flows west from a region of high pressure over the dry Great Basin to lower pressure off the California coast, According to Accuweather. As that cool interior air flows over and through mountain passes, it accelerates, sinks and compresses.

Forecasters say weaker winds will hit on Saturday night and Sunday, and that there will be no relief until the county gets rain.

The winds are common in California in the colder months, but they can sometimes help spread dangerous wildfires.