NEW YORK — Flights resumed, but slowly. The New York Stock Exchange got back to business, but on generator power. And with the subways still down, great numbers of people walked across the Brooklyn Bridge into Manhattan in a reverse of the exodus of 9/11.
Two days after superstorm Sandy rampaged across the Northeast, killing at least 70 people, New York struggled Wednesday to find its way. Swaths of the city were still without power, and all of it was torn from its daily rhythms.
At luxury hotels and drugstores and Starbucks shops that bubbled back to life, people clustered around outlets and electrical strips, desperate to recharge their phones. In Manhattan’s meatpacking district, a line of people filled pails with water from a fire hydrant.
Governor Andrew Cuomo said that parts of the subway would begin running again Thursday, and that three of seven tunnels under the East River had been pumped free of water, removing a major obstacle to restoring full service.
‘‘We are going to need some patience and some tolerance,’’ he said.
On Wednesday, both were frayed. Bus service was free but delayed, and New Yorkers jammed on, crowding buses so heavily that they skipped stops and rolled past hordes of waiting passengers.
New York City buses serve 2.3 million people on an average day, and two days after the storm they were trying to handle many of the 5.5 million daily subway riders, too.
As far west as Wisconsin and south to the Carolinas, more than 6 million homes and businesses were still without power, including about 650,000 in New York City, Mayor Michael Bloomberg said.
The mayor said 500 patients were being evacuated from Bellevue Hospital because of storm damage. The hospital has operated using generators since the storm. About 300 patients were evacuated from another Manhattan hospital Monday after it lost generator power.
Bloomberg also canceled school for the rest of the week, and the Brooklyn Nets, who just moved from New Jersey, scratched their home opener against the Knicks on Thursday.
Still, there were signs that New York was flickering back to life and was not as isolated as it was a day earlier.
Flights resumed at Kennedy and Newark airports on what authorities described as a very limited schedule. Nothing was taking off or landing at LaGuardia. Amtrak said trains will start running in and out of New York again on Friday.
The stock exchange, operating on backup generators, came back to life after its first two-day weather shutdown since the blizzard of 1888. Mayor Michael Bloomberg rang the opening bell to whoops from traders.
‘‘We jokingly said this morning we may be the only building south of midtown that has water, lights, and food,’’ said Duncan Niederauer, chief executive of the company that runs the exchange, in hard-hit lower Manhattan.
Most Broadway shows returned for Wednesday matinees and evening shows.
The Navy is sending three large-deck amphibious ships to waters off of New York and New Jersey to assist in storm recovery and relief, according to the Navy’s chief of information.
The Pentagon said in a separate update on military assistance that 10,000 Army and Air Force National Guard personnel have been mobilized to provide support in the 13 states that were hit hardest by Sandy.
In New Jersey, the National Guard used trucks to deliver ready-to-eat meals and other supplies to heavily flooded Hoboken and rushed to evacuate people from the city’s high-rises and brownstones. The mayor’s office issued a plea for people to bring boats to City Hall for use in rescuing victims.
Natural-gas fires erupted in Brick Township, where scores of homes were wrecked in the storm. And some of the state’s barrier islands, which took a direct hit from Sandy on Monday night, remained all but cut off.
In New York, masses of people walked shoulder-to-shoulder across the Brooklyn Bridge to get into Manhattan for work, reminiscent of escape scenes from the Sept. 11 terrorist attack and the blackout of 2003.
They entered an island sharply divided between those who had power and those who did not.
In Manhattan at night, it was possible to walk downtown along an avenue and move in an instant from a mostly normal New York scene — delis open, people milling outside bars — into a pitch-black cityscape, with police flares marking intersections.
People who did have power took to social media to offer help to neighbors.
‘‘I have power and hot water. If anyone needs a shower or to charge some gadgets or just wants to bask in the beauty of artificial light, hit me up,’’ Rob Hart of Staten Island posted on Facebook.
A respected New York steakhouse in the blackout zone, Old Homestead, realized its meat was going to go bad and decided to grill what was left and sell steaks on the sidewalk for $10. A center-cut sirloin usually goes for $47.
‘‘Give back to the people of New York,’’ said Greg Sherry, the steakhouse’s co-owner. He said it had served nearly 700 people on Wednesday.
Simon Massey and his 9-year-old son, Henry, took one last walk near their powerless apartment in downtown Manhattan before decamping to a friend’s place in Brooklyn where the electricity worked.
They live on the 10th floor of a 32-floor building, where they were flushing the toilet with water from their filled tub and cooking on their gas stove.
‘‘I’m feeling scared,’’ said Henry, who was home from third grade for a third straight day.
‘‘It just feels really, really weird. New York’s not supposed to be this quiet.’’