Metro-area morning commuters today will navigate 1 to 2 inches of new snow on top of ice. Add to that the severe cold, with temperatures falling to -5 in downtown Minneapolis and -10 in the outlying suburbs, and strong winds making it feel like it's -25 to -30. And there is one additional hazard: salt applied to highways and roads is not as effective in subzero cold.

To the north and west, conditions are likely to be even colder and less passable. Already Sunday night, schools in Duluth and Proctor, Minn., and nearby Superior, Wis., had announced that they will be closed today, an action likely to be widespread given snow amounts and wind speeds expected by morning.

Relief from the cold is not in the forecast anytime soon. Meteorologist Paul Douglas said an even colder arctic front may arrive before Christmas.

On Sunday afternoon, arctic air blew out the relatively mild weather, including temperatures hovering near 40 degrees, that the metro area had enjoyed over much of the weekend.

Wet roads quickly turned icy, causing a few cars to spin off roads, but there were no fatal or serious-injury car accidents as of 7 p.m., "a pleasant surprise" given several deadly crashes last weekend, said Lt. Mark Peterson, a spokesman with the State Patrol. He noted that many college students were returning home for the holidays over this weekend.

Two southbound Metro Transit light-rail trains stalled around 1:30 p.m. when ice clogged the power lines above them, forcing transit officials to bus passengers from Franklin Avenue to the Mall of America, said spokesman Bob Gibbons. Full service was restored about three hours later.

Farther north and west, snowfall was far more formidable, halting all travel in some places. Roads and shops were shut down and holiday concerts were canceled as residents holed up against blizzard-like conditions.

Blowing snow and poor visibility forced transportation officials to shut down Interstate 94 between Moorhead and Fergus Falls, Hwy. 10 between Moorhead and Detroit Lakes, and Hwy. 210 between Breckenridge and Fergus Falls.

Clay County Sheriff Bill Bergquist said the Minnesota National Guard was standing by in northwestern Minnesota to aid with any emergencies overnight.

"They have a tracked vehicle they say can go right over the snow," he said.

Travelers stranded along I-94

At the Super8 Motel in Fergus Falls, stranded travelers hunkered down for the night.

"There is nowhere else to go," said manager Kathy Frees. "The roads are closed."

By late evening, more than a foot had fallen in Isabella, near Duluth; 10 inches blanketed International Falls, and 11 inches covered Bovey, on the Iron Range. Park Rapids got at least a foot of snow; Bemidji, about 9 inches.

Mark Voxland had some advice for anyone remotely tempted to venture out in Moorhead.

"Sit tight and just enjoy looking out the window," said Voxland, mayor of the Red River Valley town. "There isn't anything going on. Everyone is hunkered down inside, doing their Christmas cards."

Both North Dakota and South Dakota closed major highways and urged people to stay home.

The National Weather Service estimated that as much as 13 inches of snow had fallen at Williston, N.D., and about a foot in Bismarck, and strong wind was whipping up the powdery snow, cutting visibility.

Bismarck's temperature at 9 a.m. Sunday was 10 below zero, but the wind made it feel more like 35 below.

North Dakota officials also closed Interstate 94, from the Minnesota border to Jamestown, along with shutting down I-29 from the South Dakota border to Canada.

In Fargo, the Cass County Sheriff's Office said visibility was down to zero, with heavy drifting on the roads.

The South Dakota Highway Patrol said I-90 was closed for 200 miles from Chamberlain west to Rapid City, and that police were sweeping the closed section to remove any stranded motorists.

Many were prepared

Many North Dakotans had been preparing for the storm since Wednesday.

"We had a lot of cancellations for the weekend. People were watching the weather," said Dee Martial, manager of a Ramada Limited motel off I-94 in Bismarck.

"We even had a lot of people on Friday who were supposed to stay through the weekend. They left early," she said. "With income the way it is, they don't want that added expense of the hotel."

The Associated Press contributed to this report. Thomas Lee • 612-673-7744