WEATHER: Blanketed

Snowy, slippery conditions in the area Saturday contributed to a semitrailer accident on Interstate 29 just one mile south of Grand Forks.

No one was injured in the accident that left the semitrailer driven by Stephen Shaw, 38, Charlottetown, New Brunswick, on its passenger side blocking both northbound lanes of I-29.

Shaw was headed south from Winnipeg to Tulsa, Okla., about 4 p.m. Saturday when he saw two vehicles stopped on the road in front of him, according to the North Dakota Highway Patrol. The two vehicles had stopped to help other motorists whose vehicles were in the ditch.

Shaw was forced to steer to the left to avoid the vehicles, overturned and ended up in the northbound lanes, according to the patrol.

"It's nice to help people out," said patrol Capt. Kevin Robson. "But the highway patrol asks that you please not stop to help people in the ditch."

Robson said any vehicles stopped on the roadway can create a hazard, and passersby should instead continue to drive and just dial 911.

"Just let us know what and where, and we'll send a trooper out," Robson said.

The semi was moved to the east ditch and remained there overnight because the truck, which was carrying peat moss, needed to be emptied before it was removed, Robson said. That wasn't possible Saturday night in the storm.

Even troopers are at risk when they park their vehicles on the side of the road to do their job, Robson said.

"Every winter, we have at least one car in the state that gets hit," he said. "We just hope none of our troopers get hurt."

Snow advisory

Northeastern North Dakota and northwestern Minnesota were under a snow advisory all day Saturday until 6 a.m. today. Most of northern Minnesota was under a winter storm warning until 6 a.m. today.

Snow accumulation in Grand Forks had reached more than 4 inches by Saturday evening and continued to fall. Some areas in Grand Forks County received as much as 5.6 inches.

Walhalla, N.D., had about 5 inches by 8:30 p.m. Saturday and Langdon, N.D., in Cavalier County had 4 to 5 inches. Minto, N.D., received 3 inches and McVille, N.D., had 4.

Areas in Beltrami County, Minn., received as much as 5 inches of fresh, fluffy snow and Thief River Falls, Minn., got 5 to 6 inches. Crookston and Fosston, Minn., were on the high end of accumulation with 6 to 8 inches. The Duluth Airport had received 6.8 inches by 7 p.m.

Road reports showed all roads in all of eastern North Dakota were either snow-covered or had scattered snow or drifts. Snow, blowing snow and snow cover caused snow fog in many areas in North Dakota, and traffic speeds were reduced.

Speeds were reduced in Grafton, Larimore, and Michigan, N.D., and most areas in Grand Forks were either snow-covered or had reduced visibility.

U.S. Highway 2 was snow-covered from Grand Forks Air Force Base to Grand Forks, and I-29 was snow-covered around Grand Forks. Caution was advised in the Fargo metro area by the state Department of Transportation because of extremely icy conditions.

A crash on Interstate 94 in Fargo involved a dozen vehicles including a passenger bus, patrol Capt. Jim Prochniak told The Associated Press.

He said two people were seriously hurt when their vehicle slid off I-29 north of Fargo near Harwood, N.D., and hit an overpass support pillar in the median.

A semitrailer rolled over on I-94 near Casselton, N.D.

Vehicles are "bumping into one another like pingpong balls out there," Prochniak said.

Driving conditions in Mahnomen County, Minn., will be difficult until 10 a.m. today because of icy patches, snow, drifting snow and gusty winds. Conditions in Beltrami, Clearwater and Lake of the Woods counties in Minnesota also are difficult for the next half day, according to the Minnesota Department of Transportation. Packed snow, packed snow patches, ice, heavy snow, reduced visibility and wind will make driving in those counties difficult.

For route-specific conditions, call 511.

Effects on flightsThe weather did little to disrupt Northwest Airlines flights in the region during Saturday's storm, however. No flights were diverted into the Grand Forks International Airport, and NWA operated at 99 percent completion factor systemwide through late Saturday afternoon, according to spokesman Dean Breest.

"Considering the size of the storm and the size of the operation, things are running very smoothly," he said. "Everybody is out there making sure everything is running smoothly."

The success is because of careful planning and the advance storm warning, Breest said.

"The small amount of passengers who were inconvenienced were put on other flights for the most part," he said.

Northwest said it would allow passengers planning to fly this weekend to rebook for a different date without penalty. The change applied to passengers flying to, from, or through Minnesota, Wisconsin, or Michigan on Saturday or today. Passengers can rebook their travel for Nov. 30 to Dec. 4.

Hundreds of flights were canceled in Des Moines, Chicago and Milwaukee. Jets slid off runways in Des Moines and Madison, Wis., AP reported.

The storm also canceled Iowa presidential campaign stops Saturday for Republican candidate Mitt Romney and Democrat Hillary Clinton.

The storm and related warnings also covered parts of Nebraska, Iowa, Wisconsin, South Dakota, Illinois and Michigan. Snow, sleet and freezing rain cut off power to many in Iowa and Illinois.