The most devastating storm in decades to hit the most densely populated US region has cut off modern communication and left millions without power, as thousands who fled their waterlogged homes wondered when and if life would return to normal.
A weakening Sandy, the hurricane-turned-fearsome superstorm, killed at least 50 people, many hit by falling trees, and is inching inland across Pennsylvania, ready to bank towards western New York state. Behind it: a dazed, inundated New York City, a drenched Atlantic Coast and a moonscape of disarray and debris - from unmoored shore-town boardwalks to submerged mass-transit systems to delicate presidential politics.
"Nature," said New York City Mayor Michael Bloomberg, assessing the damage to his city, "is an awful lot more powerful than we are." Sandy has killed 18 people in New York City, the mayor said. The dead included two who drowned in a home and one who was in bed when a tree fell on an apartment. A 23-year-old woman died after stepping into a puddle near a live electrical wire.
More than 8.2 million households were without power in 17 states as far west as Michigan. Nearly two million of those were in New York, where large swaths of lower Manhattan lost electricity and entire streets ended up under water - as did seven subway tunnels between Manhattan and Brooklyn at one point, the Metropolitan Transportation Authority said.
The New York Stock Exchange was closed for a second day from weather, the first time that has happened since a blizzard in 1888. The city's subway system, the lifeblood of more than five million residents, was damaged like never before and closed indefinitely, and Consolidated Edison said electricity in and around New York could take a week to restore.
The scope of the storm's damage is not known yet. Though early predictions of river flooding in Sandy's inland path were petering out, colder temperatures made snow the main product of Sandy's slow march from the sea. Parts of the West Virginia mountains were blanketed with two feet (0.6 metres) of snow by Tuesday afternoon, and drifts four feet (1.2 metres) deep were reported at Great Smoky Mountains National Park on the Tennessee-North Carolina border in the South.
With Election Day a week away, the storm also threatened to affect the presidential campaign. Federal disaster response, always a dicey political issue, has become even thornier since government mismanagement of Hurricane Katrina, which devastated the Gulf Coast in 2005. And poll access and voter turnout, both of which hinge upon how people are impacted by the storm, could help shift the outcome in an extremely close race.
By Tuesday afternoon, there were still only hints of the economic impact of the storm. Airports remained closed across the east coast and far beyond as tens of thousands of travellers found they could not get where they were going. Forecasting firm IHS Global Insight predicted the storm will end up causing about 20 billion dollars (£12.4 billion) in damages and 10 billion dollars to 30 billion dollars in lost business. Another firm, AIR Worldwide, estimated losses up to 15 billion dollars - big numbers probably offset by reconstruction and repairs that will contribute to longer-term growth.
In Moonachie, New Jersey, north of Manhattan, water rose to five feet (1.5 metres) within 45 minutes and trapped residents who thought the worst of the storm had passed. In a measure of its massive size, in the Midwest waves on southern Lake Michigan rose to a record-tying 20.3 feet (6.1 metres). High winds spinning off Sandy's edges clobbered the Cleveland area early on Tuesday, uprooting trees, closing schools and flooding major roads along Lake Erie.
The presidential candidates' campaign manoeuvrings revealed the delicacy of the need to look presidential in a crisis without appearing to capitalise on a disaster. President Barack Obama cancelled a third straight day of campaigning, scratching events scheduled for Wednesday in Ohio, in Sandy's path. Republican challenger Mitt Romney resumed his campaign with plans for an Ohio rally billed as a "storm relief event".