Weather alerts are in effect from California to the Texas Panhandle, and rounds of heavy mountain snow, rain and strong winds are expected to impact much of the western U.S. in the coming days.

       As of Thursday afternoon, mountain snow is falling at higher elevations in the Cascades down into the northern Sierra Nevada. Also, heavy rain is moving through parts of California, particularly through Southern California.

       MORE: Winter storms could bring extreme weather to the East and West coasts this week

       Officials are warning that torrential rain could trigger flash flooding, mudslides and debris flows, especially across regions burned by wildfires. A flood watch has been issued from Orange County, California, to San Diego.

       Several feet of heavy mountain snow is expected to fall across much of the Sierra Nevada in California though Sunday. Some of the highest peaks in the Sierra Nevada could see up to 10 feet of snow by the end of the weekend.

       David Swanson/Reuters

       A fireman aids a stuck driver as a major storm hits California with rain and snow flooding streets, in Los Angeles, Dec. 14, 2021.

       Peter Morning/MMSA via AP

       In this photo provided by Mammoth Mountain Ski Area, MMSA, a snow plower removes snow in Mammoth Mountain in Mammoth Lakes, Calif., Dec. 15, 2021.

       Strong winds could increase avalanche risk in parts of the region, officials warn. An avalanche warning is in effect through at least Friday morning for parts of the region, including the greater Lake Tahoe area.

       Also, the Rockies will eventually see at least a foot of snow heading into the weekend. Winter weather alerts are in effect across much of the mountain west with wind alerts in some areas as well.