Deep freeze grips northern U.S. from Minnesota to Maine MINNEAPOLIS (Reuters) - Frigid arctic air held the U.S. Midwest and Northeast in its icy grip on Wednesday, with the cold so dangerous that municipal emergency warming centers opened up and ski resorts shut down. The National Weather Service warned the wind chill could make the temperature feel like 40 degrees below zero Fahrenheit (minus 40 degrees Celsius) in parts of Northern Minnesota until noon on Thursday. Wintry conditions from Minneapolis to Washington marked the coldest conditions in many parts of the United States in four years, but were nowhere near the record lows for January, meteorologists said. "This cold that we are experiencing right now came straight from the arctic," said Tom Kines, an AccuWeather.com senior meteorologist. Washington, D.C., reported its coldest weather in four years, reaching 16 degrees Fahrenheit (minus 9 degrees Celsius) at Reagan National Airport early Wednesday. The National Weather Service issued a wind chill warning for New Hampshire until Wednesday evening, with values as low as 43 degrees below zero (minus 42 degrees Celsius) because of steady winds up to 20 miles per hour and gusts up to 30 mph. New Hampshire's Wildcat Mountain ski area said it would be closed to skiers on Wednesday and Thursday as temperatures, forecast to drop to 10 degrees below zero Fahrenheit (minus 23 degrees Celsius), made for "unsafe conditions" for skiers and workers. The deep freeze had forced some Minnesota school districts to delay openings or cancel classes and activities on Tuesday, and some ski areas to close early due to the wind chills. "It won't take that much wind to get things a little bit colder than they really seem to be," National Weather Service meteorologist Kevin Kraujalis said. Temperatures in Minnesota were on par with New York state, New Hampshire, Vermont and Maine. Connecticut's governor Dannel Malloy urged towns and cities to open warming centers and at least four municipalities did, including Bristol, Torrington, Meriden and West Haven, said Scott DeVico, spokesman for the Connecticut Department of Emergency Services & Public Protection. At least 22 people seeking shelter called an emergency 211 phone line overnight, he said. Warming centers were open across New York City. In Chicago on Wednesday, a five-story warehouse, that caught fire in frigid cold on Tuesday, was covered in ice as water from the fire hoses froze. Additional reporting by Scott Malone in Boston and Ian Simpson in Washington; Editing by Barbara Goldberg and Bob Burgdorfer