The eastern and central United States were gripped by a deep freeze on Tuesday, with record low temperatures in the wake of a deadly storm expected to moderate in the coming days.
The late-winter storm left behind frigid temperatures after pushing freezing rain and snow from the Mississippi Valley to the Atlantic coast on Monday.
"Tuesday will likely be the coldest morning from New York City to Washington, D.C., until next winter," the AccuWeather forecasting service said.
Temperatures across the eastern and central United States were about 30 Fahrenheit (15 Celsius) below normal, it said.
The National Weather Service said the mercury plunged to minus-1 F (minus-18 C) at Washington Dulles International Airport, tying a monthly record.
Baltimore Washington International Airport posted 4 F (minus-15.5 C), breaking a record for March set in 1873, it said.
The latest in a series of Arctic weather systems to grip the winter-weary eastern United States, the cold front stretched from the Canadian border to deep into Texas, where a winter storm warning was in effect.
The severe cold and icy roads prompted the federal government to open its Washington offices with a two-hour delay after being closed on Monday. Schools, colleges and local governments throughout the region were closed or opening late.
Rising temperatures are expected for central and eastern states later in the week, forecasters said.
Carl Barnes, a National Weather Service meteorologist in Washington, said temperatures are expected to top 50 F (10 C) on Saturday, a normal Washington reading for March.
"That kind of gives perspective of how we've been under normal for the last couple of weeks," he said.
The storm was blamed for at least six deaths, most of them from traffic accidents on slippery roads. A woman in Bowie, Maryland, died on Monday from a likely heart attack after shoveling snow, a spokesman for the Prince George's County fire department said.
About 600 U.S. flights were canceled and about 500 delayed on Tuesday in the wake of the bad weather, according to airline tracking site FlightAware.com. About 8,000 flights were canceled or delayed on Monday.