Denver faced its heaviest snows of the season early Friday, while parts of Wyoming and New Mexico bundled up against stormy weather and frigid temperatures.
Phoenix braced for a subfreezing Friday morning, a rarity in the desert city.
Packing more punch, the storms Thursday blasted some states with fierce wind gusts and heavy rains or snows, closing hundreds of miles of roads and dumping a snowy mix of precipitation on the edges of Phoenix.
Officials closed a road into Yosemite National Park in California after a rock the size of a dump truck tumbled onto the road, and strong winds created snow dunes on rooftops, front yards and streets across mountainous areas of Arizona.
Snow and ice forced an hours-long closure of the two major thoroughfares in northern Arizona, stranding motorists south of Flagstaff and the Grand Canyon. People in Phoenix were stunned at the sight of snow-type flurries.
Major highways were also shut down in parts of New Mexico, Colorado, Wyoming, Montana and Nevada.
Forecasters were predicting more of the same in eastern parts of Wyoming and New Mexico. And snow could fall at a rate close to an inch an hour in Denver, which usually has around 25 inches of snow by the New Year but had just 1.5 inches.
The Denver and Colorado Springs areas could get up to a foot of snow as the storm lingers through Friday, and the eastern plains could see up to 7 inches, the National Weather Service said.
Snow and strong winds in northeastern Wyoming were expected overnight accompanied by subzero temps. The weather service Thursday posted blizzard and winter storm warnings for parts of eastern and southern Wyoming.
Meanwhile, a cold front was continuing its sweep across New Mexico with overnight snows in the east.
New Mexico State police Thursday were discouraging drivers from traveling east of Albuquerque. An 80 mile stretch of Interstate 40 from Moriarty to Santa Rosa was closed for about five hours but reopened before midnight. Still, a temporary shelter is in place in Moriarty for stranded travelers.
On Thursday, the Silverton Mountain resort in Colorado reported 22 inches of snow, but only about 120 people were on the mountain because officials closed highways leading to the ski area for avalanche control and because of adverse conditions, resort co-founder Jen Brill said.
R.A. Burrell, of Colorado Springs, left home around 3 a.m. to avoid getting stuck on the way to the extreme ski area and made it before the lift started running.
"I thought we'd really just come on a magical day, which is what it turned out to be," he said during a break from making turns. "We just got lucky."
United Airlines, the dominant carrier at Denver International Airport, canceled 32 United and United Express flights from Denver on Thursday, spokesman Rahsaan Johnson said.
Drivers in Arizona wanting to know how to get around the storms overwhelmed a state hotline that provides automated updates on road conditions.
Dorothy Brooks, of Dallas, was creeping along Interstate 40 at 20 mph on her way to Las Vegas, passing vehicles stuck on the side of the road, when she pulled into a Bellemont gas station to wait out the storm.
"It's devastating," she said, above the cry of a 9-month-old baby she was pushing through the aisles. "You can't call Mother Nature anyway. You never know when she's going to burst out."
Forecasters said strong winds in California were expected to die down by early Friday, allowing a cold air mass to create frost and freeze problems in the region.
The California Highway Patrol reported downed trees on various Los Angeles-area freeways and streets. One gust north of Los Angeles was clocked at 94 mph.
Residents in the Phoenix area couldn't believe what they were seeing when white stuff starting falling from the sky. The wintry mixture of snow and hail had the appearance of snowflakes.
"Believe it or not, but I am looking out my window in Scottsdale, Az & its SNOWING! Never thought I would see this!" former Arizona Cardinals quarterback Kurt Warner tweeted.
Inmates housed at the city's Tent City jail facility were being issued extra blankets and pink thermal underwear - part of Sheriff Joe Arpaio's odd method for punishing prisoners.
Further east, severe winds and heavy snowfall blanketed the Dakotas and Minnesota, snarling traffic and closing roads and causing a massive pileup of nearly 100 vehicles on Interstate 94 near Fargo.
In the snow-laden Sierra Nevada, search teams found the body of a woman who disappeared while snowboarding at a Lake Tahoe-area resort, officials said. Icy roads led to a collision on U.S. 50 in Nevada, killing a 26-year-old woman.
A camping Boy Scout troop of seven boys and three adults had to be rescued after a snowstorm stranded them near Pocatello, Idaho.
Gordon Mason of Rockford, Ill., was taking it all in stride. The 62-year-old semi-truck driver was browsing through movies at a travel center in Arizona, grateful that something was open to occupy his time.
"The way the lot is, it's going to take a while to clear the trucks so the rest of us could get out," he said. "I'm not even going to try until tomorrow."
Contributing to this report were Associated Press writers Felicia Fonseca in Bellemont, Colo., John Antczak and Robert Jablon in Los Angeles, Garance Burke in Fresno, Gillian Flaccus in Orange County, Haven Daley in Sonoma County and Sudhin Thanawala and Terry Collins in San Francisco.