Washington, Baltimore and Philadelphia were digging out Sunday from a massive snowfall that paralysed the Mid-Atlantic region and left hundreds of thousands without power.

At its heaviest, the blizzard dumped 97 centimetres of snow from Friday morning to Saturday evening in Elkridge, Maryland, just south of Baltimore.

Washington recorded 45 centimetres at Reagan National Airport, the city's second-largest snowfall ever. Philadelphia registered its second-biggest total at centimetres. Baltimore-Washington International airport had 63 centimetres.

Dulles International Airport, which had more than 75 inches of snow, had 'limited operations' Sunday, the Washington airport authority said. Reagan National remained closed for snow removal.

Washington's Metro transit system continued Sunday to serve only below-ground stations, and its bus system remained closed. Amtrak cancelled 18 trains Sunday between Washington and New York.

'This was an epic storm,' said Andrew Ulrich, a meteorologist for AccuWeather.com Inc, in State College, Pennsylvania. 'The sheer amount of snow was amazing.'

Snow fell for more than 24 hours, ending by early evening Saturday and leaving clear skies and a crisp, cold, starry night.

Sunday morning brought sunshine, which allowed some thawing of cleared pavements, but the high temperature was not expected to break zero celsius. Most of the snowfall came in wet, heavy flakes, which was turning rock-hard in the bitter cold now forecast to grip the region for the next several days.

In suburban Maryland and Virginia, main roads were ploughed, but most residents remained stranded on side streets that are unlikely to be cleared before Monday or Tuesday.

Most schools in the Maryland and Virginia suburbs around Washington announced by Sunday morning that classes would be cancelled for Monday, and some more outlying suburbs have already cancelled Tuesday classes.

Another storm was headed to the region, due to hit Tuesday evening and Wednesday, with 15 to 30 centimetres expected from Washington to Philadelphia.

Heavy, wet snow and fallen trees took their toll on the power grid. More than 100,000 customers were still without power Sunday in the Washington-Baltimore region. Another 160,000 customers in Pennsylvania were without power, according to Governor Ed Rendell's office, Bloomberg news agency reported.

Washington's mall, the Washington Monument and the Smithsonian Institution museums remained closed Sunday to keep streets empty for ploughing.

The wet, heavy snow caused roofs to partially collapse on at least half a dozen buildings, including a school and a church, local broadcaster WJLA reported.

At least two people had died in a traffic accident in Virginia, local reports said.

President Barack Obama, whose adopted hometown of Chicago is used to harsh winters, has chided the nation's capital in the past for Its fear of snow. But he called the latest storm 'Snowmageddon here in DC' when addressing a Democratic Party meeting, held Saturday despite the weather.

His motorcade was not immune from the slick conditions, with two vehicles colliding on the way to the event and a tree branch falling on a press vehicle at the White House.

The storm could be the worst in 90 years in the Washington region after final snowfall is totalled, local meteorologists said.

The storm system - a result of the El Nino weather effect, meteorologists said - has been heading up from the south all week, where it dropped rain and lesser amounts of snow.

The Washington region already received a massive snow storm in December when 40 centimetres fell, and this weekend's storm was a rare second major storm within one season. The record snowfall for the capital region was 70 centimetres in January 1922.