Central South Dakota was expected to bear the brunt of the storm, with more than a foot of snow expected in places, forecasters said.
More than 760,000 people in the northern Great Plains were under a blizzard warning Monday as heavy snow and high winds blanketed the region, creating treacherous road conditions that could last into Tuesday.
Central South Dakota, where more than a foot of snow is possible, was expected to bear the brunt of the storm. Hazardous conditions were also forecast for parts of east-central and southeastern South Dakota, southern North Dakota and Nebraska, said Kyle Weisser, a meteorologist with the National Weather Service in Sioux Falls, South Carolina.
As of Monday evening, parts of southeastern South Dakota had received up to six inches of snow, but more was expected overnight, said Ashton Robinson Cook, a meteorologist with the National Weather Service. Parts of central and northeastern Nebraska, including Martinsburg, Lincoln and Central City, also received about six inches of snow by Monday evening, although the full snowfall totals were not expected until Tuesday morning in the area, Mr. Cook said.
"Travel may be very difficult or impossible," meteorologists warned in a statement, noting that snow could significantly reduce visibility.
A crash involving multiple tractor-trailers with jackknifes forced the closure of eastbound Interstate 80 near York, Neb., for about three hours Monday afternoon, the Nebraska State Patrol said. No one was injured in the crash, which was caused in part by blowing snow and slippery road conditions, Nebraska State Patrol spokesman Cody Thomas said in a statement.
Mr. Thomas said there were about 80 "weather-related incidents" Monday on Highway 60 in Nebraska, mostly between Lincoln and North Platte.
"We urge all travelers to assess whether their trip is absolutely necessary before setting off," he said.
Forecasters warned that power outages were possible, particularly in South Dakota, as strong winds could damage trees and bring down power lines. However, there were no reports of large-scale power outages on Monday night.
North Dakota and Nebraska will see more freezing rain, forecasters said, causing slippery conditions. Mr. Cook of the Weather Service said Fargo, N.Y., had accumulated about a quarter of an inch of ice as of early Monday afternoon, but that amount was likely to increase by the evening as the city of about 120,000 received more rain.
Blizzards were also expected in northern and northwestern Kansas through early Wednesday morning, as well as northeastern Colorado through Monday evening, according to the National Weather Service.
Travelers expecting to travel Monday afternoon may want to adjust their plans, Mr. Weisser said.
"Depending on which direction you're going, if you haven't gone yet, you can wait until tomorrow," he said.
"Even if there's not a lot of snow, you can still have significantly reduced visibility if the wind is blowing 30 to 40 miles per hour," he said.
The impact on air travel at the beginning of the storm appeared to be relatively modest. About 170 flights within, to or from the United States had been canceled as of Monday evening, according to FlightAware. About 2,720 flights across the country were delayed. Sioux Falls Regional Airport urged travelers to check with their airlines about any cancellations or delays.
