A commuter bundles up against extreme cold conditions Tuesday, Jan. 22, 2013, in Chicago. Temperatures in the area were hovering around zero with sub-zero wind chill reading hitting 10 below. (AP Photo/M. Spencer Green)

An Arctic blast has gripped the Midwest and Northeast, with a perilous combination of bitterly cold air and gusty winds making it feel like winds 50 degrees below zero and enough snow and ice to cancel schools and make driving treacherous.

In Washington, D.C., it was 15 degrees at Reagan National Airport on Wednesday morning, the coldest it has been there in nearly four years, since March 3, 2009.

The bitter conditions were expected to persist into the weekend in the Midwest through the eastern half of the U.S., said Shawn DeVinny, a National Weather Service meteorologist in suburban Minneapolis.

Authorities suspect exposure has played a role in at least four deaths so far.

"I am wearing a Snuggie under a top and another jacket over that," said Faye Whitbeck, president of the chamber of commerce in International Falls, Minn., a town near the Canadian border where the temperature was minus 30 on Tuesday morning. The so-called "Nation's Icebox" reached a balmy 3 below for a high. "I pulled out a coat that went right to my ankles this morning and I wore two scarves."

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Winds blasting across the Great Lakes over the past few days into Tuesday also resulted in up to 18 inches of snow dumped over northeast Ohio, northwest Pennsylvania and upstate New York.

Schools, set to resume classes on Tuesday after Monday's national holiday in honor of Dr. Martin Luther King, were canceled in some states including Massachusetts and Ohio.

Wind chill advisories were in effect throughout the Midwest and Northeast, with last winter's unseasonably warm temperatures making this January blast seem even colder, forecasters said.

As a result, temperatures felt like 50 degrees below zero in isolated sections of the upper Midwest and to minus 30 degrees in parts of Maine, Vermont, New Hampshire and upstate New York.

But as cold as it's been, there hasn't been a remarkable number of record lows, said Nick Wiltgen, a meteorologist with The Weather Channel.

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"These temperatures have not even come close to ranking among January's 10 coldest days or nights on record at long-term observation sites," Wiltgen said.

In Milwaukee, where the temperature was just 2 degrees at noon Tuesday, police checked under freeway overpasses to find the homeless and urge them to find a shelter. The United Way of Greater Milwaukee has donated $50,000 to two homeless shelters so they can open overflow centers.

"We're incredibly relieved," said Donna Rongholt-Migan, executive director of the Cathedral Center, a Milwaukee shelter that received $25,000. "I was walking my dog last night and I couldn't feel my legs just after walking around the block."

The plunging temperatures made life plenty miserable for plumbers.

Workers in Madison had to repair at least four water main breaks since Sunday afternoon. Jim Gilchrist, a third-generation plumber in the Chicago suburb of Oak Park, said he received about five or six calls Tuesday from people with frozen water pipes in their homes. Few pipes had actually burst -- yet.

"We'll probably get those calls later, as pipes begin thawing" and develop a split, Gilchrist said. Today they just know they don't have water; tomorrow they will have water spraying."

At least two fires in southern Wisconsin were blamed on property owners using heaters or other means to thaw frozen pipes. In one case, a dairy barn was destroyed, and in the other, a mobile home was lost. No one was hurt.

Information from Reuters and the Associated Press was used in this report.