Every year, a hot and dry wind periodically sweeps across the mountains of southern California bringing the risk of wildfires.

These winds, common in autumn and early winter, are created when high pressure develops over the Great Basin and low pressure occurs off California’s Pacific Coast. The clockwise flow around the high pressure accelerates downhill from the higher elevations of the Great Basin to sea level.

The winds also accelerate by the funneling effects of canyons and narrow passes found across southern California’s mountain range.

If the winds gusting in excess of 60 mph wasn’t enough, the downhill winds compress, causing temperatures to rise sharply and humidity levels to plummet.  These two combinations dry out the vegetation, making it easy for a fire to start and spread quickly. A spark from a downed powerline, cigarette, hot exhaust or campfire is all that is needed for a fire to start and spread quickly.

The humidity and wind speed forecasts are available directly on the Weather & Radar app. The high winds can be tracked using the WindRadar.