DES MOINES, Iowa — Weekend storms in the nation's northern half knocked out power to thousands of customers today and created nightmarish conditions for holiday travelers coast to coast on the first official day of winter.

Gusty winds in the Midwest, where wind chills dipped to minus 30 degrees or lower, produced whiteout conditions that contributed to at least two vehicle pileups, in Wisconsin and Michigan.

And blizzard warnings were issued for parts of Maine, where up to 24 inches of snow was expected. Forecasters warned that strong wind could create whiteout conditions and deep drifts.

"This is a classic nor'easter," said meteorologist John Cannon. "It's got all the features."

Parts of Iowa and Illinois were under blizzard warnings. Power was knocked out to more than 35,000 customers Sunday in Illinois shortly after being restored to most who had lost it after a storm last week, utilities said.

"There was so much icing down there on the trees and power lines; then the wind is coming through and knocking things down," said ComEd spokeswoman Kim Johnson.

More than 70,000 homes and businesses in Indiana remained in the dark after an ice storm that struck Thursday. Wind gusts topping 30 mph hindered repair work, officials said.

Wind gusts up to 35 mph blew snow and contributed to a crash involving at least 30 vehicles today in southwestern Michigan on Interstate 94, a major route between Chicago and Detroit, officials said. At least one person was seriously injured in the crash, which shut down six miles of eastbound lanes north of Stevensville, state police said.

At least a dozen vehicles were involved in a pileup today on Interstate 43 in Wisconsin's Ozaukee County that briefly shut down southbound lanes. Some people were injured, the sheriff's office said, but it wasn't clear how many.

Temperatures in northern Maine early Sunday included minus 40 on the Big Black River in Aroostook County and minus 35 in Allagash. Gov. John Baldacci announced a noon start for state government offices on Monday.

The storm battering Maine also produced sleet and freezing rain in New York and New Jersey, delaying flights at Newark Airport by an average of two hours. Some arrivals at Logan International Airport in Boston were delayed by more than three hours.

And as the weather interfered with airports in Northern states, George Bush Intercontinental Airport in Houston had delays on average of about five hours.

And while officials in the Pacific Northwest were relieved Sunday that a storm there failed to meet expectations, hundreds of travelers nonetheless lingered at Seattle-Tacoma International Airport, waiting for their next flight.

At Seattle's Greyhound bus terminal, dozens were stranded overnight, passengers said. No Greyhound buses were running there today.

Interstate 90, Washington state's main east-west route, reopened today across Snoqualmie Pass in the Cascade Range.

Washington Emergency Management spokesman Rob Harper said fewer than 5,000 customers lost power, and state officials said county emergency operations were scaling back or closing.