People cross the road as a sign warns of heavy snow on Sunday in Denver, Colo. A winter storm closed roads, impacted flights, and knocked out power in Arizona, Wyoming, Nebraska, and Colorado through the weekend.

Caption

People cross the road as a sign warns of heavy snow on Sunday in Denver, Colo. A winter storm closed roads, impacted flights, and knocked out power in Arizona, Wyoming, Nebraska, and Colorado through the weekend. / Getty Images

A winter storm that snarled traffic, knocked out power and disrupted flights in parts of Arizona, Wyoming, Colorado and Nebraska through the weekend is forecast to spread into the Midwest Monday.

The storm rolled into parts of the Rocky Mountains late Saturday into Sunday, dropping several feet of snow and heavy rain. Gusty winds caused whiteout conditions and residents were warned to stay off roads.

Some drivers on Arizona's Interstate 40 Saturday night didn't make it home in time to heed the warning, forcing some to spend Saturday night on the road, after icy conditions caused several crashes and shut the highway down.

Lingering effects of the storm are expected to cause rough conditions though early Monday as residents dig out from under record breaking levels of snowfall.

Several school districts in Colorado ordered classes to be canceled on Monday.

"Even as the storm subsides, travel across the state will be extremely challenging on Monday morning," Chief Matthew Packard of the Colorado State Patrol said.

In Wyoming, Gov. Mark Gordon said high winds and more snowfall are expected in the state and government operations would be limited. He tweeted for residents to "stay safe and avoid unnecessary travel."

Additional snow is predicted to fall in parts of South Dakota, southern Minnesota, and northern Iowa. The National Weather Service in Phoenix warned strong winds, of up to 40-50 mph, are expected through Monday afternoon.

Road closures

Whiteout conditions closed dozens of roads in Colorado throughout most of Sunday — including several sections of Interstate 70, according to the state's Transportation Department. Sections of Interstate 25 and 76 were closed as well.

Small avalanches were reported, impacting Colorado Highway 14 in the north-central region on Sunday, Colorado's DOT said.

Major highway routes in Nebraska were also shut though Sunday due to blizzard conditions that left feet of snow on roads. Several sections of I-80 and I-25 were also closed in Wyoming.

Snow plowing operations in Wyoming's Casper area Sunday afternoon were temporarily suspended due to a lack of visibility, the region's transportation department said.

"We had several plows drive off the roadway due to limited to zero visibility," the agency said on its Facebook page.

Power outages, canceled flights

More than 54,000 homes and businesses were without power Sunday afternoon in Colorado. By Sunday night at 11 p.m., 26,000 were still without power.

The winter weather also forced the closure of all six of Denver International Airport's runways through Sunday. The main road leading into the airport was also closed due to disabled vehicles.

The late-season winter storm dropped 24.1 inches at the airport, enough to make the storm the fourth-largest in the city's history, according to Colorado Public Radio.

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