MINNEAPOLIS — A powerful winter storm that caused whiteout conditions and treacherous roads in parts of the Upper Midwest is blamed in at least three fatal accidents, officials said.

The Minnesota State Patrol said it responded to more than 100 crashes, more than 200 spinouts and eight jackknifed semis from late Thursday until mid-day Friday. Northern Minnesota snowfall reached 18 inches at Finland, along Lake Superior’s north shore. Twelve inches fell in Brainerd, according to the National Weather Service.

The driver of a pickup truck was killed Thursday when he collided with another vehicle on a snow-covered highway in Dunn County, North Dakota. The Highway Patrol says the vehicles crashed when visibility was reduced by blowing snow kicked up by a plow. Officials identified the driver who died as 37-year-old Jared Maturin, of Jeanerette, Louisiana; the driver and three passengers in the other vehicle were not hurt.

Also Thursday, a small bus and an SUV collided on a slippery road near Big Lake, Minnesota, leaving one bus passenger dead. Sherburne County sheriff’s officials said 47-year-old Marilyn Balogi of Zimmerman was killed, while seven other passengers, the bus driver and the SUV driver were taken to hospitals. Big Lake is about 40 miles northwest of Minneapolis.

In central Minnesota’s Crow Wing County, a pedestrian was struck on a road by a pickup with a plow blade. Sheriff’s officials say road conditions and visibility were very poor at the time of the accident around 8:30 p.m. Thursday. The victim was identified as 51-year-old Michael Donnay, of Merrifield, who was pronounced dead at the scene.

Snow from the same system also left roads blanketed in Nebraska. The Nebraska Transportation Department listed nearly two-thirds of the state’s highways as partially or fully covered with snow Friday morning. The department pulled its plows from clearing highways in parts of northeast Nebraska because visibility was so limited.

In North Dakota, the Highway Patrol is urging drivers to be cautious around snowplows working to clear highways after multiple crashes this week, including the fatal wreck. The patrol is also encouraging drivers to slow down when approaching emergency vehicles with lights flashing.

Officials said a trooper’s vehicle was hit Friday by a driver while parked on the shoulder of Interstate 94 in Fargo. Officials said the driver lost control and sideswiped the patrol vehicle, but that the driver and trooper weren’t injured. Shortly after, two more vehicles crashed and three others spun out in the same area.