11.57am: New York's Metropolitan Transport Authority has posted this video of a flooded Long Island Rail Road tunnel.
11.34am: The New York Times is reporting that the death toll from Sandy stands at 38.
11.29am: US correspondent Jack Tame says he will be live on TV ONE News at MIDDAY. He tweets: "Entering the black zone of Manhattan once again... very weird."
11.16am: The Virginia Department of Emergency Management says power outages across the state now stand at 94,000 and are "continually decreasing".
11.11am: New York Mayor Michael Bloomberg says he spoke to President Barack Obama earlier on Tuesday local time but "while we'd love to have them", he didn't accept Obama's offer to come to New York.
"I was flattered that he offered to come but I think the thing for him to do is go to New Jersey and represent the country."
Bloomberg says New Jersey represents all storm-hit areas.
11.10am: Web-only video: Peter Williams brings you the latest on superstorm Sandy.
11.07am: New York Mayor Michael Bloomberg summarises Burke's comments saying the vast majority of New Yorkers without power should not expect to have it restored before the weekend.
11.04am: Consolidated Edison CEO Kevin Burke tells media crews are continuing to work on restoring power to New York.
He says deliberately shutting some power stations to try to avoid them being damaged appeared to have been a successful strategy.
11.02am: Mayor Bloomberg says he understands the New York Marathon will go ahead as scheduled.
11.01am: New York Mayor Michael Bloomberg says Coney Island Hospital has been evacuated but all others in the city remain open.
He says residents affected by Sandy can apply for federal aid from disasterassistance.gov .
The mayor warns New Yorkers to avoid trees, which he says could be waterlogged.
"More limbs and whole trees could come down," he says. "Stay away from city parks - they're closed until further notice."
10.57am: New York Mayor Michael Bloomberg tells reporters 18 people died in the city as a result of the storm.
"Sandy hit us very hard - it was a storm of historic intensity."
Bloomberg says he has viewed the worst-hit areas of the city, including Breezy Point in Rockaway. "To describe it as looking like the pictures we've seen at the end of World War Two is not overstating it," he says.
But Bloomberg says things are improving. "We have a plan for recovery and that plan is already beginning," he says. "This is the end of the downside."
10.50am: Ontario Minister of Energy Chris Bentley says hydro crews have been working "throughout the night and day today to restore power".
He says as of 4.30pm (9.30am NZT), 37,000 people were without power - down from 113,000 at the peak of the storm.
10:32am: Mayor Michael Bloomberg's update on live on nyc.gov . has been delayed until about 5.45pm (10.45am NZT).
10.30am: New Jersey Governor Chris Christie says he has surveyed the damage on the shore and will be giving an update at 7.15pm (12.15pm Wednesday NZT) live on his website .
10.14am: New York Governor Andrew Cuomo says more than two million New Yorkers remain without power.
10.00am: The National Hurricane Center says strong winds will continue into Tuesday night local time (Wednesday NZT) over portions of the North East, Appalachians and Great Lakes.
It says water levels along the coast have been subsiding but warns: "The combination of storm surge and the tide could still cause normally dry areas near the coast to be flooded by rising waters."
There will be additional snowfall in the mountains of West Virginia into far western Maryland with "isolated amounts of up to 15 inches (38cm)", it says.
9.56am: The National Hurricane Center says Post-Tropical Cyclone Sandy "continues to weaken over Pennsylvania".
In its 5pm (10am NZT) update, the centre says Sandy is about 80km east north-east of Pittsburgh, in Pennsylvania, and has maximum sustained winds of 72km/h.
9.52am: CNN reporter Erin Burnett says she has seen 19 ambulances heading towards Breezy Point, in Rockaway, New York - a neighbourhood that has been badly hit by flooding and fire.
9.50am: The Federal Office of Emergency Management warns residents not to walk or wade through flood water. "It can contain harmful chemicals, toxins, and even raw sewage," it tweets.
9.45am: In Canada, Emergency Management Ontario says 50,000 people are without power due to Sandy.
9.39am: This is the moment the crane on a massive NY building collapsed under the pressure of superstorm Sandy.
9.32am: New York Mayor Michael Bloomberg says he will give a briefing on Sandy at 5.30pm local time (10.30am NZT). It will be streamed live on nyc.gov .
9.29am: The New York City Coast Guard says its station in the city suffered storm damage "but crews are search and rescue response ready".
9.24am: NY State assembly member Phillip Goldfeder says Rockaway, New York, is still in "recovery and rescue mode".
"I think a lot of people are still trapped and under water," he tells CNN.
He says in southern Queens, people have started going door-to-door to check on residents but that process hasn't yet begun in the neighbourhood.
"We just don't know who was in and who was out."
9.19am: NY State assembly member Phillip Goldfeder tells CNN "80 or 90 homes completely burned to the ground" in the neighbourhood of Breezy Point in Rockaway, New York.
He says Sandy's winds quickly spread fire through the area, where wood-framed houses have been built close together.
9.12am: Ocean City Mayor Jay Gillian tells CNN Sandy missed the worst tide for the New Jersey city.
"We got very lucky - we just dodged a bullet," he says.
"It could have been a lot worse but what we got was something I've never seen before in my life."
Gillian says the city's downtown was "devastated". "We're very, very fortunate no-one was hurt."
8.59am: New York Governor Andrew Cuomo tweets that 2,091,451 New Yorkers are without power.
8.58am: The City of Philadelphia says government agencies, courts and public schools will be open on Wednesday.
8.51am: The US government says federal agencies in Washington will reopen on Wednesday.
8.46am: The US Nuclear Regulatory Commission says three nuclear reactors - two in New York and one in New Jersey - were shut down during the storm. One experienced an electrical fault, another automatically shut down in response to "electrical grid disturbances" and the third was manually shut down when high river levels affected its water pumps.
New Jersey's Oyster Creek nuclear plant is still in alert due to "high water levels in its water intake structure", the NRC says.
8.34am: New Jersey Governor Chris Christie tells reporters a wall of water measuring more than 1.5 metres surged up the Hackensack River and swept through three towns overnight.
"It was not a dam or a levee; it was just a natural berm that was overwhelmed by...an unprecedented tidal surge," he says.
Christie says residents had almost no warning but no fatalities have yet been reported as a result of the surge.
8.23am: Met Service forecaster Dan Corbett tells TV ONE Breakfast the winds around the centre of Sandy are easing but the storm is still dumping water as it travels over Pennsylvania.
8.17am: National Grid says power has been restored to more than 150,000 customers in New York and Long Island and that nearly 600 crews are working to repair damage.
8.11am: The White House says President Obama will travel to New Jersey on Wednesday local time to view the damage from Sandy.
8.04am: US President Barack Obama says in the storm's darkness "I think we also saw what's brightest in America".
He praises Americans' "spirit of resilience and strength" and their willingness to help their neighbours, which he says will allow storm-hit areas to recover.
8.00am: US President Barack Obama says he wants every US federal agency "to lean forward".
"No bureaucracy, no red tape, get resources where they're needed as fast as possible."
He says his message to state governors and mayors is: "We are going to do everything we can to get resources to you and make sure that any unmet need is identified."
7.52am: US President Barack Obama says the storm is "not yet over" and other communities could still be affected.
"It is still moving north," he tells reporters. "So I want to emphasise there are still risks of flooding, there are still risks of downed power lines, risks of high winds."
Obama says the federal government will do all it can to help local authorities cope with damage.
7.44am: The New York Stock Exchange is expected to open on Wednesday.
7.35am: The BBC's Laura Trevelyan describes a "post-apocalyptic scene in Manhattan".
7.32am: NZ Ambassador Mike Moore tells TV ONE Breakfast Sandy has been "catastrophic" for New Jersey and New York.
But he says modern forecasting allowed officials to be prepared, limiting damage. Moore advises Kiwis in affected US areas: "Listen to the authorities - they know what they're talking about."
7.30am: In Washington DC, NZ Ambassador to the US Mike Moore tells Breakfast the city has "missed most of it" but has been shut down for a couple of days.
Moore says some trees have been damaged at the New Zealand embassy but that it fared worse in a previous storm.
7.26am: Jack Tame says it could take four or five days before NYC's transport system is back up and running.
7.24am: US correspondent Jack Tame tells Breakfast all public transport in New York City remains suspended and a third of Manhattan is still without power.
6.39am: Sandy, still classified as a post-tropical cyclone, is expected to turn north and track back into New York state tonight, before heading into Canada on Wednesday, the National Hurricane Center says.
6.28am: New York mayor Michael Bloomberg says: "We knew this was going to be a very dangerous storm, and it has met our expectations."
6.23am: New Jersey Governor, Chris Christie, says the damage from superstorm Sandy is "unprecedented, like nothing we've ever seen before".
6.22am: Approximately 50 homes were destroyed over night by fire in Queens.
6.20am: US Correspondent Jack Tame tweets that latest reports put the death toll at 35 .
6.16am: "We're only beginning to get a sense of what happened," Bradley says
6.15am: Bradley says eight US states are bracing for snow today.
6.14am: He said America has " not really seen anything like this" before. "In New York to see water on the streets of Manhattan, and have the stock exchange closed for two straight days, which has not happened since the 1800s, this is just remarkable," he says.
6.13am: Bradley says there are more than 8 million people without power across the US.
6.11am: ABC reporter Tahman Bradley speaks live from Ocean City, Maryland, to TV ONE's Breakfast. He says "Sandy was the monster that we feared", adding that it will take some days to assess the devastation.
5.55am: President Barack Obama has declared a "major disaster" in New York state.
5.53am: Reports are coming in that 33 people have died since the storm hit the US east coast.