Portions of Montana, the Dakotas and Wyoming were hit by a slow-moving snowstorm that knocked out power, closed roads and dumped up to 11 inches by Wednesday.

Thousands of power outages were reported and some schools were closed by the storm, which began Tuesday. Drifting snow contributed to road closings.

About 155 miles of Interstate 94 (search) west from Mandan, N.D. to the Montana border was closed to traffic Wednesday morning after the major winter storm brought heavy, wet snow and strong winds that snapped trees and power lines, canceled classes and left vehicles in the ditch.

"It's really treacherous — heavy, deep snow. Visibility is just really poor. It's so heavy that vehicles just can't push through it," Highway Patrol Capt. Mark Bethke said.

"I've got semis all over the place, stuck," said Lori Moldenhauer, who works at the Tiger Discount truck stop along Interstate 94 in Dickinson.

"In the parking lot, I've got semis pulling off the interstate because they can't make it anywhere because its' a whiteout out there," Moldenhauer said early Wednesday. "I've got travelers stuck here in cars — they can't see going down the road."

The Highway Patrol also advised no travel in the Minot and Rolla areas in north-central North Dakota. Schools were closed (search) in much of the north central and western parts of the state, including Minot State and Dickinson State Universities.

Montana-Dakota Utilities spokesman Dan Sharp said power outages were reported from Miles City, Mont., to Bismarck, after the heavy, wet snow snapped trees and power lines. He said crews had been out all night trying to restore power.

More than 11,000 customers throughout the region lost power due to the storm, officials said.

Don Kuntz said it took him three hours to drive from Bismarck to Dickinson on Wednesday morning, and he stopped to help stranded drivers.

"I should have stayed in Bismarck," he said.

"We've got equipment out working, but it's wet, heavy snow and it's going to pack, and it's going to turn to solid ice and we're not going to be able to keep up with it," said Alan Walter, Minot's public works director, in advising no travel in the city.

The National Weather Service said it received a report of 12 inches of snow around Halliday and 10 inches at Fairfield, north of Belfield in Billings County. Minot reported between 8 inches and 10 inches, the weather service said.

The Dickinson area could get about 10 inches of snow by Wednesday night, when the storm was expected to move out, forecasters said.

The state had 90 degree temperatures just a few days earlier. Bismarck reported 92°F on Oct. 1, National Weather Service meteorologist Harlyn Wetzel said.

The heavy snow avoided Bismarck, which had rain throughout Tuesday night and light snow the next morning.

In Rugby, street department worker Dan Bolk said he and his co-workers were ready for the snow. They normally prepare in early October, he said.

The city of about 3,000 has about a dozen miles of streets to plow during the winter, Bolk said.

"We're tired mowing grass, raking leaves," he said. By Christmas, he said, they likely would be tired of the snow as well.

The storm was expected to taper off Wednesday afternoon and move out of the state by the weekend.

By Friday, the weather service said, high temperatures are expected to range from the lower 50s in the northeast to the mid-60s in the west.

In Utah, the ski industry was looking up.

Snowbird Ski & Summer Resort received its first snow of the year Tuesday with 6 inches atop 11,000-foot Hidden Peak. More snow was falling Wednesday.

"There are still projects to be done before winter arrives, but this first snowfall has put smiles on the faces of people all around Snowbird," said Snowbird President Bob Bonar.