Four people were killed in separate crashes on wet and icy roads Monday night as the State Patrol counted at least 100 crashes around Minnesota.
Spokesman Sgt. Jesse Grabow says heavy snow made the roads treacherous for much of the day in northwestern Minnesota.
"Things started to improve a little bit throughout the evening, as MnDOT plows were able to get out and work the roads up and put them in better shape," he said.
Roads are still listed in difficult driving condition from International Falls to Bemidji, over to Duluth and down to St. Cloud, and the Patrol says that drivers should slow down, follow from a safe distance and keep their headlights on.
Today all Duluth public, private, parochial and charter schools are closed because of the heavy snow falling.
Forecasters say the weather is likely to worsen tonight, with as much as 8 inches of snow and near-blizzard conditions in the Red River Valley into Wednesday.
The National Weather Service in Duluth says a wide swath of northeastern Minnesota and northwestern Wisconsin could get more than 10 inches of snow through Wednesday, with a foot possible on the Iron Range.
Temperatures are expected to bitterly cold later in the week. Yesterday four people died in weather related road accidents.
SLOW GOING IN THE DAKOTAS
Some roads in South Dakota are in poor driving condition because of the storm. Freezing rain caused the majority of headaches Monday. The National Weather Service says snow and gusty winds will be the main problem Tuesday and Wednesday, followed by bitterly cold temperatures late in the week.
Snowfall in North Dakota Tuesday and Wednesday is expected to total 2-4 inches north of state Highway 200 and 6-8 inches south of the highway that cuts across the central part of the state. Some areas also got a few inches on Monday. Northern South Dakota could see 5-10 inches of snow.
As Minnesota's lakes start to freeze, safety officials are warning outdoor enthusiasts to be cautious when venturing out onto any lake that's covered or partially covered with ice, especially those with aeration systems.
Aerators are installed on around 280 Minnesota lakes to help prevent winterkill of fish. But they also create areas of open water and thin ice that are hazardous to anglers, snowmobilers and skiers.
DNR aquatic biologist Marilyn Danks says open water areas created by aeration systems can shift or change shapes depending on weather conditions. And she says leaks may develop in air lines, creating new areas of weak ice or open water.
Aerated lakes are required to have warning signs at all commonly used access points, along with thin ice signs marking the area's perimeter.
The Associated Press contributed to this report.