Stripped of its bustle and mostly cut off from the world, New York was left wondering Tuesday when its particular way of life — carried by subway, lit by skyline and powered by 24-hour deli — would return.

Mayor Michael Bloomberg and the power company said it could be the weekend before the lights come on for hundreds of thousands of people plunged into darkness by what was once Hurricane Sandy.

Bloomberg said it could also be four or five days before the subway, which suffered the worst damage in its 108-year history, is running again. All 10 of the tunnels that carry New Yorkers under the East River were flooded.

Sandy 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.

"This was a devastating storm, maybe the worst that we have ever experienced," Bloomberg said.

For the 8 million people who live here, the city was a different place one day after the storm.

In normal times, rituals bring a sense of order to the chaos of life in the nation's largest city: Stop at Starbucks on the morning walk with the dog, drop the kids off at P.S. 39, grab a bagel.

On Tuesday, those rituals were suspended, with little indication when they would come back. Schools were shut for a second day and were closed Wednesday, too.

Coffee shops, normally open as close as a block apart, were closed in some neighbourhoods. New York found itself less caffeinated and curiously isolated from the world, although by afternoon it had begun to struggle back to life.

Some bridges into the city reopened at midday, but the Brooklyn-Battery Tunnel, connecting Brooklyn to Manhattan, and the Holland Tunnel, between New York and New Jersey, remained closed. And service on the three commuter railroads that run between the city and its suburbs was still suspended.

Governor Andrew Cuomo said bus service would be restored at 5 p.m. local time, on a limited schedule but free. He said he hoped there would be full service on Wednesday, also free.

The New York Stock Exchange was closed for a second day, the first time that has happened because of weather since the 19th century, but said it would reopen on Wednesday.

Swaths of the city were not so lucky. Consolidated Edison, the power company, said it would be four days before the last of the 337,000 customers in Manhattan and Brooklyn who lost power have electricity again.

For the Bronx, Queens, Staten Island and Westchester County, with 442,000 outages, it could take a week, Con Ed said. Floodwater led to explosions that disabled a power substation on Monday night, contributing to the outages.

New Yorkers were left without power to charge their iPods and Kindles and Nooks for the subway. Not that there was a subway. People clustered around electrical outlets at a Duane Reade drugstore to power up their phones.

At a small market called Hudson Gourmet, in Manhattan's Greenwich Village, cashiers made change by candlelight and shoppers used flashlights to scour the shelves.

The mayor added: "We will get through the days ahead by doing what we always do in tough times — by standing together, shoulder to shoulder, ready to help a neighbour, comfort a stranger and get the city we love back on its feet."