Winter Storm Warning for Nine States As up to 24 Inches of Snow Forecast

Winter storm warnings are in place for parts of nine states as a powerful atmospheric river storm that made landfall in California on Sunday continues to move eastward, bringing a wintry mix of precipitation to the West.

The National Weather Service (NWS) issued alerts for Alaska, Arizona, California, Colorado, Montana, Nevada, New Mexico, Utah and Wyoming, warning of heavy snow, high winds and the continued threat of flooding.

It comes as areas of flooding continue to pose a threat in California, despite new precipitation expected to ease off from Thursday or Friday. Heavy rainfall over the past few days has caused mudslides and saw trapped residents clinging to trees.

The flooding prompted California Governor Gavin Newsom to declare a state of emergency for several counties in Southern California on Sunday. The Associated Press reported that, as of Thursday, there had been nine storm-related deaths in the state, citing officials.

The state had already faced several inches of rainfall last week after a "plume of moisture" from the subtropics made its way eastward on Thursday and Friday. The extended storm period has led to historic levels of precipitation.

In its latest forecast, the NWS said that unsettled weather would continue for the West, with locally heavy snowfall. Wintry precipitation will appear in the Northern Plains, while there was a chance of thunderstorms for the Upper Midwest on Thursday, spreading into the south on Friday.

A series of fresh waves from the storm will keep the chance of precipitation high for Western states, with the heaviest amounts of snow falling in the Four Corners region, the meteorological agency said.

"Fortunately, rainfall amounts have come down, and despite the very wet antecedent conditions in California and the Desert Southwest, chances for any additional flooding look to be very low," the NWS said.

The NWS warned, though, that the San Bernardino County and Riverside County mountains could see up to 24 inches of snow above 7,000 feet.

In addition to the ongoing impacts on California, as much as 16 inches of snow in mountain regions of southern Nevada "will create very dangerous avalanche conditions, hazardous to anyone near deep and unstable snowpack," the NWS warned.

More than 20 inches of snow is expected in parts of northern and central Arizona, with periods of intense snowfall of up to two inches an hour and winds of up to 45 miles an hour creating blowing snow and reducing visibility.

Conditions are set to persist in higher elevation regions of Utah, where additional snow accumulations of up to 20 inches are expected to fall after four feet of snow was predicted on Wednesday.

In northern New Mexico, a further 10 inches of snow is anticipated after Wednesday's totals, with wind gusts of up to 40 miles an hour. Up to a foot of extra snow is expected in areas of western Colorado above 7,500 feet, where winds could reach up to 45 miles an hour.

This weather will continue into southern Wyoming, where the Sierra Madre mountain range is set to receive additional snow accumulations of up to 16 inches after being forecast two feet on Wednesday, as well as winds of up to 50 miles an hour.

Heavy snow is also expected in west-central Montana, where up to five inches of snow is expected to fall.