Superstorm Sandy is a "wake up call" that could lead to billion dollar flood defences being created in New York City.
Three of New York's top 10 highest floods have occurred in the last two and a half years, and the latest disaster has fuelled calls for major investment in flood defences.
"If that's not a wake-up call to take this seriously I don't know what is," said climate change expert Ben Strauss.
"The city is extremely vulnerable to damaging storm surges just for its geography, and climate change is increasing that risk."
State governor Andrew Cuomo is now considering storm surge barriers - which could cost up to $10bn - or a levee system.
Darkness continued to envelope a large stretch of the Manhattan skyline
"The construction of this city did not anticipate these kinds of situations. We are only a few feet above sea level," he said.
"As soon as you breach the sides of Manhattan, you now have a whole infrastructure under the city that fills - the subway system, the foundations for buildings."
With at least 50 people killed along the east coast - most by falling trees - and millions affected by the high winds, power cuts and flooding, President Barack Obama cancelled campaign appearances in key state Ohio to oversee the government response.
He is due to visit New Jersey to survey some of the widespread devastation caused by superstorm Sandy in eastern US and Canada.
He described the disaster as "heartbreaking for the nation".
The President is fighting a close race with Republican rival Mitt Romney and the White House has been keen to portray him as a strong leader ahead of election day on November 6.
More than eight million homes have been left without electricity by the biggest storm to hit the country in generations, which swamped parts of New York's subways system and Lower Manhattan's financial district.
Flood water from Sandy surrounds homes in South Bethany, Delaware
Much of the Manhattan skyline was still in darkness on Tuesday night and it is feared it could be days before electricity is restored to some of those cut off.
Forecasters predict the storm could end up causing around $20bn (£12bn) worth of damages in the US.
Sky News weather presenter Nazaneen Ghaffar said the bad weather will continue.
"The storm is still reacting with cold air from the west, so there will be further heavy snowfall as well as inland flooding," she said.
"Rainfall totals could reach around 6-8 inches, and winds will remain gale force in strength.
"The forecast suggests that the centre of the low will move northwards from western Pennsylvania into the west of New York and then into Quebec by Thursday."
Businesses and homes along New Jersey's shore were wrecked and communities were submerged under floodwater across a large area on Tuesday.
After seeing pictures of the shore, State Governor Chris Christie said: "The devastation is unthinkable."
A strong supporter of fellow Republican Mr Romney, Mr Christie also praised Mr Obama's federal response to the disaster.
Amid the despair, talk of recovery was already beginning.
"It's heartbreaking after being here 37 years," Barry Prezioso of Point Pleasant, New Jersey, said as he returned to his house in the coastal community to survey the damage.
"You see your home demolished like this, it's tough. But nobody got hurt and the upstairs is still livable, so we can still live upstairs and clean this out. I'm sure there's people that had worse. I feel kind of lucky."
The storm reached as far inland as Ohio and caused thousands of flight cancellations, while mobile phone network outages also were widespread.
Meanwhile, parts of West Virginia were buried under 3ft (1m) of drifting snow from the storm.
Mr Obama has issued federal emergency decrees and declared "major disasters" in both New Jersey and New York.
Speaking during a visit to Red Cross headquarters in Washington, he said: "New Jersey, New York in particular have been pounded by this storm. Connecticut has taken a big hit."
More than 80 homes in New York City's borough of Queens were destroyed in a fire caused by the storm.
New York Mayor Michael Bloomberg, who toured the area, said: "To describe it as looking like pictures we've seen of the end of World War Two is not overstating it. The area was completely levelled.
"Chimneys and foundations were all that was left of many of these homes."
Neighbour John Frawley, 57, said: "I stayed up all night. The screams. The fire. It was horrifying."
Hundreds of miles away from Sandy's turbulent centre, winds were churning up the waters of Lake Michigan to near record levels.
Officials in Chicago warned people to stay away from the lakefront, and parts of the bicycle path along the shore was closed.
The strong wind and rain has had other unexpected consequences.
Police in New Haven said a skeleton was revealed beneath the town green that may have been there since Colonial times.
Police spokesman David Hartman said a woman was with other bystanders looking at a fallen oak tree, and spotted bones in the upturned roots.
Hurricane Sandy - which was reclassified as a post-tropical storm upon making US landfall - had already killed 69 people in the Caribbean.
Many islands were ravaged by the storm, with an estimated $16.5m (£10.3m) worth of damage in Jamaica and 70% of crops destroyed in southern Haiti.
A Foreign Office spokesperson says that according to 'best esimates' there are 50,000 British tourists and 300,000 residents in the area affected by superstorm Sandy.