The second storm in less than a week buried parts of the U.S. Mid-Atlantic under record snowfalls, closing schools, cancelling flights and wreaking havoc on the region's roads.

By early evening Wednesday, winter snowfall records were broken in Baltimore, Washington, and Philadelphia as the white stuff piled on top of a metre of snow already on the ground from last weekend's "Snowmageddon."

Baltimore's previous winter snowfall record of 158.8 centimetres was broken, and Washington set a new record of 139 centimetres, breaking the old record -- set in 1898-99 -- by more than one centimetre.

In Philadelphia, 178.6 centimetres of snow has fallen so far this winter, breaking the previous record of 166.37. Driving conditions were so bad in some parts of Pennsylvania that the governor closed some highways and warned people to stay home.

Entrance ramps to highways were blocked and the Pennsylvania National Guard had Humvees loaded with supplies for motorists who decided to venture out and risked getting stranded.

Twenty-five vehicles were involved in two separate accidents on Pennsylvania's Interstate 80, leaving one person dead and 18 injured.

"For your safety, do not drive," Gov. Ed Rendell said. "You will risk your life and, potentially, the lives of others if you get stuck on highways or any road."

Across the state, more than 60,000 people were without power Wednesday, many having never had it restored after last weekend's storm.

By midday Wednesday, up to 40 centimetres of the white stuff had fallen in parts of western Maryland, while 23 centimetres was recorded at Washington's Reagan National Airport.

Heavy snow also fell in New Jersey and New York City, which had been under a blizzard warning issued by the U.S. National Weather Service.

The weather service predicted between 25 and 40 centimetres for the Big Apple, prompting the closure of city schools. The United Nations also remained closed for the day.

As snow piled up on city streets, Broadway producers offered discount tickets to their shows to fill seats left empty by poor weather forecasts.

Before making its way up the East Coast, the storm first hammered the Midwest, where it is blamed for hundreds of flight cancellations, as well as at least four traffic deaths in Michigan. In Chicago, a pickup truck plowing snow hit and killed a 71-year-old woman.

Road crews were out in full force on the East coast, with thousands of workers attempting to plow and salt roads. Pennsylvania reported some workers were staying on the job for up to 16-hour shifts, and Maryland was running out of salt.

Hundreds of flights cancelled

Flight schedules at Canadian airports lit up red with cancellations Wednesday as the storm made its way across the Mid-Atlantic region.

At Toronto's Pearson International Airport, flights to Washington, New York, Newark, and Philadelphia were cancelled, along with flights to Windsor, Ont., which was hit hard by the same weathermaker affecting the U.S. destinations.

Air Canada posted a travel alert to its website advising passengers that the airline's flights to Washington's Dulles and Reagan National Airports, Thurgood Marshall International Airport in Baltimore, Philadelphia International Airport, Logan International Airport in Boston, LaGuardia Airport in New York and Liberty International Airport in Newark may be delayed or cancelled due to the severe winter weather.

The airline also warned of possible delays or cancellations of flights to Washington, Baltimore and Philadelphia on Thursday.

The storm has prompted the company to revise its ticketing policy for passengers booked on affected flights.

"Those customers wishing to make alternate travel arrangements can do so without penalty, space permitting, using our online rebooking tool," the airline said on its website.

Porter Airlines, which flies out of Toronto's island airport, showed most flights to Newark and Boston were cancelled Wednesday. However, as of late Wednesday evening, the airline's website indicated that Thursday's flights to both cities would be departing on time.

WestJet flights have not been affected by the storm because the airline does not fly to the Mid-Atlantic region.

Storm shutters U.S. government

The White House, Congress and federal government buildings were shuttered Wednesday for a second straight day due to the weather in Washington, along with all public schools and universities, CNN's Samantha Hayes told CTV's Canada AM.

About 230,000 federal workers in Washington have been off since Friday afternoon, when the first storm began. The U.S. House announced it was scrapping the rest of its workweek.

Officials announced late Wednesday that federal agencies would also stay closed Thursday.

"With the exception of road crews and emergency personnel and those that have to be out it's going to be another atypical weekday here in Washington D.C., another quiet afternoon as the snow falls," Hayes said.

Wind gusts of up to 70 kilometres per hour made driving conditions so bad around Washington that the capital and some outlying suburbs pulled plows off the roads.

Heavy snow is also being blamed for the collapse of a roof and part of a wall at a storage building used by the Smithsonian Institution in Suitland, Maryland. Officials said it was unlikely that any artifacts had been damaged.