Thousands of Americans have been placed on alert for hazardous winter weather conditions, with snow and ice to impact travel.

Isolated heavy downpours, wind gusts up to 50 mph, lightning and even a remote chance of a tornado are expected through Friday.

The soggy weather that has drenched Southern California since the weekend has mostly moved out of the area, giving residents a brief respite from the rain before another storm moves in later in the week.

Varying snowfall amounts will hit seven states on Thursday and Friday, prompting numerous warnings and advisories across the U.S.

The Phoenix Fire Department confirmed a roof collapse at Desert Sky Mall at 75th Avenue and Thomas Road. A dental clinic’s drop ceiling collapsed from heavy water accumulation, which spread to other stores throughout the mall, according to Capt. Todd Keller, a Phoenix fire spokesperson.

An updated winter storm watch was issued by the NWS San Diego CA on Wednesday at 9:30 p.m. valid from Thursday 10 a.m. until Saturday 10 a.m. for San Bernardino County Mountains and Riverside County Mountains.

Impacts from the incoming storm will hit nearly the entire state of California later this week, only days after flooding rainfall.

Widespread rain Thursday night with occasional showers continuing into Saturday with a slight chance of thunderstorms through Friday.