A 30-car pileup in Iowa is blamed on snow; two people killed (CNN) -- A blizzard that hammered the Midwest is expected to weaken Friday. But the road closures, school cancellations, power outages and travel delays spawned by the storm continue to cause widespread havoc and inconvenience. Many people planning Christmas trips have been stuck at Chicago's two airports -- O'Hare and Midway -- because of flight cancellations. "There is a long line of very unhappy people," said an air traveler quoted by CNN affiliate WLS. It's not a good experience. The heavy snows will "finally begin to wind down by Friday," the National Weather Service said. But strong winds are still expected to hammer the region Friday and Saturday as holiday travelers take to the roads and head to airports. The winter storm is moving over the eastern Great Lakes and the Northeast on Friday and Saturday, bringing high winds and light to moderate snowfall. The snow is not expected to be a foot or so deep, as it was in the Midwest. Blizzard warnings have been discontinued, except for a couple of mountainous West Virginia counties. The severe weather has caused problems in many areas in the past few days. Blinding snow is blamed for a 30-car pileup on Interstate 35 near Fort Dodge, Iowa. People in the middle of the blizzard shared their insights and videos with CNN iReport this week. Clarence Smith captured video of a snowstorm hitting Des Moines, Iowa, with more than an 8-inch accumulation -- the first such snowfall in three years. Kevin Cavallin, in Ames, Iowa, said that "a hefty snowstorm like this is not that unusual for Iowa." "Snow is on top of everything," said Siby Thomas, in Clive, Iowa. The steps, the backyard and the park and trees and on the jungle gym in the park. Danny Murphy, a storm chaser, called it the "worst blizzard I had seen in all my years of doing weather. Last year, we had a blizzard, but not winds this strong. At least 20,000 customers were without power in Iowa early Friday, most of them in the Des Moines area, MidAmerican Energy said. The storm was the first blizzard of the season and it certainly made travel from the Plains into the Midwest. Nebraska authorities temporarily closed much of snow-packed Interstate 80 Thursday as blowing snow dangerously reduced visibility. The interstate was reopened later, but motorists were advised to be cautious. David Bell sent CNN iReport a photo of an accident on an interstate highway in Ogallala, Nebraska, this week. The image showed trucks on an icy roadway, and Bell said the interstate was shut down later because of several accidents. He described poor visibility because of wind gusts and snow. We got around 10 to 12 inches throughout the state, and it's a wet snow. As much as 7 inches was already on the ground Thursday in parts of southern Wisconsin, and by the end of that event over a foot of snow had fallen in some areas.