LOS ANGELES (AP) — A deep chill has gripped much of California in the aftermath of a very cold storm system that brought a new layer of snow to the mountains.

Hard freeze warnings are in effect early Thursday morning for the Sacramento Valley, the northern San Joaquin Valley, the North Coast and interior valleys of the Central Coast and Southern California. Many other areas, including the north and east San Francisco Bay Area, are under freeze warnings and frost advisories.

The Los Angeles County health officer has issued cold weather alerts for several areas and is warning people to not use stoves, barbecues or ovens to heat their homes due to the risk of carbon monoxide poisoning.