A large, fast-moving snowstorm that closed sections of major highways on the Plains on Saturday was blamed for seven traffic deaths, while strong winds in Arkansas cut a 5-mile-long swath of damage, destroying buildings and leaving several people injured.

The storms in the Plains knocked out power to more than 100,000 customers and dumped more than a foot of snow on the Upper Midwest. The seven deaths all occurred on slippery Wisconsin roads.

Meanwhile, some residents in the southeastern Arkansas city of Dumas were unaccounted for after winds, and possibly a series of tornadoes, blew through and police were making a door-to-door search, authorities said. Emergency crews summoned ambulances from a neighboring county.

A Fred's Dollar Store just south of Dumas was left in a tangle of twisted metal and crumbled concrete blocks, and an overturned tractor-trailer rested in its parking lot. A power substation was destroyed and electricity was out in the area.

Forecasters said the damage could have been done by a tornado or by straight-line winds that could have exceeded 70 mph.

In Colorado, Interstate 70, a major cross-country route, was closed for about 200 miles in both directions from just east of Denver to Colby, Kan., because of blowing snow and slippery pavement, according to Colorado and Kansas highway officials.

Between Denver and the beginning of the highway closure, about 35 cars collided in a pileup in whiteout conditions Saturday morning on an icy section of I-70. No major injuries were reported.

The weather service reported wind gusts of 68 mph in the Denver area.

A number of other highways also were closed in the two states, Wyoming and Nebraska.

"Basically there's zero visibility at this time," Kansas Department of Transportation spokeswoman Barb Blue said just before noon. But many roads reopened later Saturday, including most of Interstate 80 in Nebraska, of which more than 270 miles had been closed.

Power was knocked out to 100,000 customers, primarily in Iowa, but also in Oklahoma and Nebraska.

"The snow is so wet it's sticking to power poles and power lines," said Bill Taylor of the
National Weather Service office in North Platte. About 8 inches of snow had fallen in the north-central town of Ainsworth.

In addition to the snow on the western Plains, the vast storm system spread rain and thunderstorms across parts of Arkansas, Oklahoma and Missouri, with locally heavy snow across Iowa and southern Minnesota.

The weather service posted blizzard and winter storm warnings for parts of Colorado, Kansas, Nebraska, South Dakota, Iowa, Minnesota, northern Illinois and Wisconsin.

As much as 15 inches of snow had fallen by Saturday afternoon at Galesville in southwestern Wisconsin. Up to 16 inches was possible by late Sunday in Minnesota, which would be the state's biggest snowfall so far in an unusually dry winter, the weather service said.

Flights continued operating Saturday at Denver International Airport, where thousands of travelers were stalled by a 45-hour shutdown during a pre-Christmas blizzard. The airport was on the western edge of the area of heavy snow and had only about an inch by late morning, spokesman Chuck Cannon said.

Elsewhere, however, airlines canceled 230 arrivals and departures at Chicago's O'Hare International and 40 at Midway in anticipation of snow, sleet and freezing rain, said Wendy Abrams, Chicago's aviation department spokeswoman. United Airlines planned to cancel all flights at O'Hare after 7 p.m., said spokeswoman Robin Urbanski.