Multiple wildfires, including the Palisades Fire and Eaton Fire, are raging across Southern California Thursday, leaving at least 10 dead and burning more than 27,000 acres, officials say. Police have arrested 20 suspected looters.

Southern California ‒ with sprawling cities, clogged freeways and heavy industry ‒ is already notorious for some of the worst air quality in the nation. This week's wildfires are putting millions of people at risk for immediate health problems and longer-term issues.

High pressure is building from the north and that will help to tighten the pressure gradient over southern California, producing more gusty winds.

See before and after photos from the California wildfires:

A perfect storm of weather and climate conditions made the California wildfires nearly impossible to contain once they ignited, according to experts.