A winter storm dumping snow across the US Midwest on Friday forced the cancellation of more than 600 flights at Chicago's O'Hare Airport, while slick roads and poor visibility snarled traffic across the region.
The storm was expected to drop 1 to 8 inches of snow from the Dakotas to the lower Great Lakes, with Chicago among the hardest hit among the big cities.
Up to 7 inches of snow was expected in Chicago, where Southwest Airlines also cancelled all of its flights from 2 pm to 5 pm at Midway Airport and delayed flights scheduled for 5 pm to 7 pm, according to the Chicago aviation department.
Milwaukee and Cleveland both were expected to be hit with up to 5 inches of snow. Several smaller school districts outside of Milwaukee have cancelled after-school programmes.
The storm dropped about an inch of snow on Friday morning in the Twin Cities area, where there were reports of hundreds of minor accidents on slick roads and long morning rush hour delays. Snow fall totals were heavier south of the Twin Cities.
Reports of 4 to 6 inches were common from far southern Minnesota, across northeast Iowa and southwest Wisconsin, the National Weather Service said.
The snow is expected to push into the northeast, with up to six inches of the white stuff expected from Pennsylvania through central Maine Saturday, and up to four inches in New York City.
In Washington state, which has seen unusually heavy snow, two climbers and two campers are missing in Mount Rainier National Park. Searches were suspended on Friday afternoon because of the weather, which includes 40 mph winds, poor visibility, and thick fog.
The Puget Sound region continued to see scattered power outages on Friday, affecting about 275,000 customers. Seattle is preparing for possible flooding, with crews clearing storm drains of snow and debris.