With at least 50 people dead, transit crippled in New York City and millions of people along the U.S. East Coast struggling without electricity, communities face a daunting challenge of repairing the damage wrought by superstorm Sandy.

In New York, where 18 people were killed, Mayor Michael Bloomberg surveyed the destruction in the hardest-hit neighbourhoods Tuesday. He said he saw homes so utterly destroyed only “chimneys and foundations” were left.

But despite the daunting challenge of recovery efforts, Bloomberg said “New Yorkers are resilient.”

About a third of New York’s fleet of taxis were operating Tuesday, bus service was partially restored, and the New York Stock Exchange was expected to reopen Wednesday.

U.S. President Barack Obama declared New York and Long Island a “major” disaster area.

The declaration means federal funding is now available to residents of the hardest-hit areas, who awoke to a tragic aftermath of the deadly storm that slammed ashore in New Jersey on Monday evening.

New York had seen a four-metre surge of seawater crash ashore overnight, inundating the city's tunnels and electrical systems and causing massive damage to the city's famed subway. The storm left New York with no running trains, a vacated business district and entire neighbourhoods under water.

New York's Metropolitan Transportation Authority said the subway system, which remains closed, had suffered the worst damage in its 108-year history.

As of midday Tuesday, Sandy's sustained winds were already diminishing from the 130 km/h it was packing at landfall near Atlantic City, N.J. on Monday evening.

But forecasters warn the storm system will continue to affect a region stretching from the U.S. eastern seaboard north to Canada, and as far west as Wisconsin and Illinois, as it churns across Pennsylvania before veering into western New York state sometime Wednesday.

New Jersey Gov. Chris Christie gave a bleak update at a morning news conference Tuesday, saying seaside rail lines were washed away, and there was no safe place on the state's barrier islands for him as large parts of the coast are still under water.

"We are in the midst of urban search and rescue. Our teams are moving as fast as they can," Christie said. "The devastation on the Jersey Shore is some of the worst we've ever seen. The cost of the storm is incalculable at this point."

The effects aren't contained to America's largest city. More than 7.4 million homes and businesses in an area that stretches from the Carolinas in the south to Ohio in the northeast are without power Tuesday. Tens of thousands were also without electricity in southern parts of Ontario and Quebec too, as Sandy carries its combination of rain and wind northwards.

In Canada, a Toronto woman was killed Monday evening after she was struck by a falling sign blown down in the powerful storm’s high winds.

Most of the Sandy-related wind warnings issued by Environment Canada have been called off however, except for the Sarnia region, areas along the St. Lawrence River in Quebec and Inverness County in Nova Scotia.

The storm was officially downgraded from hurricane status, but it came ashore packing a lot of energy due to its unusually low barometric pressure. Combined with a cold-weather system from the north, and the high tide of the full moon, the storm is forecast to continue wreaking havoc across a 1,300-kilometre region that's home to 50 million people through Wednesday.

Forecasters are even warning as much as one metre of snow could fall in some states, some of which has already fallen in West Virginia and other higher ground inland.

Notable effects of post-tropical storm Sandy:

  • U.S. death toll so far is 50, including 18 people in New York, and numerous others killed in a total of seven states.
  • In Canada, one woman is dead after she was struck by debris from a wind-blown sign in the west-end of Toronto Monday evening.
  • Sandy had already been blamed for 69 deaths when it tore through the Caribbean.
  • Concerns during the peak of the storm prompted shutdowns at two nuclear plants in New York and New Jersey, as well as an alert at America's oldest nuclear plant at Barneget Bay, N.J.
  • 200 patients, including those on respirators and babies in intensive care, evacuated after New York University's Tisch Hospital lost power.
  • Winds toppled a construction crane atop a 74-storey luxury high-rise in midtown Manhattan, forcing the evacuation of nearby buildings.
  • Fire destroyed at least 50 homes in the Breezy Point section of Queens.
  • Four unoccupied row houses in Baltimore collapsed in the storm.
  • Wind gusts of more than 100 km/h prompted the closure of the port in Portland, Maine.
  • Flooding in areas from Virginia to Atlantic City, where the storm washed away a 15-metre section of the famous boardwalk. New York City's now-flooded subway remains shut.
  • The Holland Tunnel connecting New York to New Jersey is closed, as is a tunnel between Brooklyn and Manhattan. The Brooklyn Bridge, the George Washington Bridge, the Verrazano-Narrows Bridge is also barricaded due to high winds.
  • More than 12,000 commercial flights are cancelled, with more expected. New York's LaGuardia, Newark Liberty and Kennedy airports are all closed.
  • One crew member of the Canadian-built HMS Bounty sunk in storm-battered seas off North Carolina was found and later pronounced dead. 14 others rescued alive, but the captain is still missing.

An estimated 360,000 residents of 30 Connecticut communities were under mandatory and voluntary evacuation orders.

While it could take days to determine the extent of the storm damage, early estimates peg the potential price tag anywhere between $10 billion and $20 billion, which could make it one of the costliest storms in U.S. history.

Ahead of Sandy making landfall Monday, U.S. President Barack Obama declared states of emergency in Massachusetts, Connecticut, Rhode Island, New York, New Jersey and Pennsylvania.

"Please listen to what your state and local officials are saying," Obama said from the White House. "When they tell you to evacuate, you need to evacuate. Don't delay, don't pause, don't question the instructions that are being given, because this is a powerful storm."

On the U.S. presidential election front, both Obama and Republican presidential candidate Mitt Romney suspended campaigning Monday, with just a week left before voting day.

Early voting was also cancelled in Maryland and Washington, D.C.