By Brendan O’Brien

MILWAUKEE (Reuters) – A record-shattering Arctic freeze kept its grip on much of the United States east of the Rocky Mountains on Tuesday but temperatures everywhere except the Northeast were expected to warm within 24 hours.

Many school districts shut their classrooms due to the cold snap, which claimed four lives over the long New Year’s weekend.

The National Weather Service issued wind chill warnings for Tuesday as dangerously low temperatures were due from eastern Montana across the Midwest into the Atlantic coast and the Northeast and down through the deep South.

School districts in Iowa, Massachusetts, Indiana, Ohio and North Carolina canceled or delayed the start of classes as bitterly cold temperatures, 20 degrees to 30 degrees Fahrenheit (11 to 17 degrees Celsius) below normal, were expected across the eastern half of the United States.

“Just the bitter cold which is just too dangerous to put kids out on the street waiting for a bus that may not come,” Herb Levine, superintendent of the Peabody Public Schools, north of Boston, told a local CBS affiliate television station.

The cold was blamed for the deaths of two men in separate incidents in Milwaukee, according to the Milwaukee Journal Sentinel. A homeless man was found dead on a porch in Charleston, West Virginia, while another man was found dead outside a church in Detroit and police said he may have froze to death, local news outlets reported.

Washington Mayor Muriel Bowser urged residents to call the city if they saw people outside.

“We want every resident to have shelter and warmth,” she said in a tweet.

Many places across the United States experienced record low temperatures over the last few days. Omaha, Nebraska, posted a low of minus 20F (minus 29C), breaking a 130-year-old record, and Aberdeen, South Dakota, shattered a record set in 1919 with a temperature of minus 32F (minus 36C).

The cold should ease across most of the country after Tuesday, but the northeastern section of the country will see a repeat of the frigid weather on Thursday or Friday as another arctic blast hits the area.

Private AccuWeather forecaster said the cold snap could combine with a storm brewing off the Bahamas to bring snow and high winds to much of the Eastern Seaboard as it heads north on Wednesday and Thursday.

(Reporting by Brendan O’Brien in Milwaukee; Editing by Raissa Kasolowsky and Jeffrey Benkoe)