The death toll in the city stood at 41 and thousands of shivering people were without electricity, making many New Yorkers recoil at the idea of assigning police officers to protect a foot race and evicting storm victims from hotels to make way for runners.
Bloomberg, who as late as Friday morning insisted that the world's largest marathon should go on as scheduled Sunday, changed course hours later after intensifying opposition from the city controller, the Manhattan borough president and sanitation workers unhappy that they had volunteered to help storm victims but were assigned to the race instead. The mayor said he would not want "a cloud to hang over the race or its participants."
"We cannot allow a controversy over an athletic event - even one as meaningful as this - to distract attention away from all the critically important work that is being done to recover from the storm and get our city back on track," the mayor said.
Around 47,500 runners - 30,000 of them out-of-towners, many of them from other countries - had been expected to take part in the 26.2-mile event, with more than 1 million spectators usually lining the route.
The race had been scheduled to start in Staten Island, one of the storm's hardest-hit places, and wind through all of the city's five boroughs. The nationally televised race has been held annually since 1970, including 2001, about two months after the 9/11 terrorist attacks.
For runners, the cancellation was a devastating disappointment.
At the midtown New Yorker Hotel, the lobby was filled with anguished runners, some crying and others with puffy eyes. In one corner, a group of Italian runners watched the news with blank looks.
"I have no words," said Roberto Dell'Olmo, from Vercelli, Italy. Then later: "I would like that the money I give from the marathon goes to victims."
Elsewhere across the metro area Friday, the recovery made slow progress. Companies turned the lights back on, and many employees returned to their desks. Many major retailers also reopened.
But patience was wearing thin among New Yorkers who had been without power for most of the week.
Gov. Andrew Cuomo told utilities to step up power repair work or risk losing business in the state. And officials said the cost of the storm could exceed $18 billion in New York alone.
From storm-scarred New Jersey to parts of Connecticut, a widespread lack of gasoline frustrated people who were just trying to get to work or pick up a load of groceries.
Lines of cars, and in many places queues of people on foot carrying bright red jerry cans, waited for hours for precious fuel. And those were the lucky ones. Other customers gave up after finding only closed stations or dry pumps marked with yellow tape or "No Gas" signs.
Bloomberg called the marathon an "integral part of New York City's life for 40 years" and insisted that holding the race would not require resources to be diverted from the recovery effort. But, he said, he understood the doubts.
"We would not want a cloud to hang over the race or its participants, and so we have decided to cancel it," Bloomberg said in a statement. "We cannot allow a controversy over an athletic event - even one as meaningful as this - to distract attention away from all the critically important work that is being done to recover from the storm and get our city back on track."
City and race officials considered several alternatives: a modified course, postponement or an elite runners-only race. But they decided cancellation was the best option.
Organizers will donate various items that had been brought in for the race to relief efforts, from food, blankets and portable toilets to generators already set up on Staten Island.
The cancellation means there won't be another NYC Marathon until next year.
"I understand why it cannot be held under the current circumstances," Meb Keflezighi, the 2009 men's champion and a former Olympic silver medalist, said in a statement. "Any inconveniences the cancellation causes me or the thousands of runners who trained and traveled for this race pales in comparison to the challenges faced by people in NYC and its vicinity."
"Bloomberg's decision came just a day after he appealed to the grit and resiliency of New Yorkers, saying, "This city is a city where we have to go on."
Mary Wittenberg, president of the New York Road Runners, the group that organizes the marathon, said canceling was the right move.
"This is what we need to do and the right thing at this time," she said.
"It's been a week where we worked very closely with the mayor's office and felt very strongly, both of us together, that on Tuesday, it seemed that the best thing for New York on Sunday would be moving forward. As the days went on, just today it got to the point where that was no longer the case."
Patrick Lynch, president of the Patrolmen's Benevolent Association - the police department's largest union - called the decision to cancel the marathon "a wise choice."
ING, the financial company that is the title sponsor of the marathon, said it also supported the decision to cancel. The firm's charitable giving arm has made a $500,000 contribution to help with relief and recovery efforts, and is matching employee donations.
Wittenberg said about 10,000 runners were expected to drop out after the storm arrived.
For now, marathon organizers are sticking to their policy of no refunds for runners, but they will guarantee entry to next year's marathon. However, Wittenberg said the group would review the refund policy.
Eric Jones said he was part of a group from the Netherlands that collected $1.5 million to donate to a children's cancer charity if the runners competed.
"We understand, but maybe the decision could have been made earlier, before we traveled this far," said Jones, whose group came to New York a day earlier.
Steve Brune, a Manhattan entrepreneur, was set to run his fourth New York City Marathon.
"I'm disappointed, but I can understand why it's more important to use our resources for those who have lost a lot," he said.
Brune said he thinks foreign runners who traveled for the race will be even more disappointed.
"When you have a significant amount of people voicing real pain and unhappiness over its running, you have to hear that. You have to take that into consideration," said Howard Wolfson, deputy mayor for government affairs and communications.
"Something that is such a celebration of the best of New York can't become divisive. That is not good for the city now as we try to complete our recovery effort, and it is not good for the marathon in the long run," he said.
Earlier in the day, race preparations seemed under way as normal.
White tents where the runners would meet were already erected. Plastic crates lined the park's wall for two blocks, with tangles of electric wires and other setup equipment where workers buzzed around. A few TV news crews set up camp.
Along the race route in Queens, a couple of marathon banners hung from street lamps.
"I'm not a fan of what he's doing," Manhattan resident Michael Folickman said of Bloomberg's decision. "I think that if the bridge is cleared and the streets are clear, I don't think it'll wreak any more havoc than what's already been wreaked."
"And I think it could be an uplifting experience for the city to have something exciting like that happen on top of this terrible hurricane," he said.
In Staten Island, Eddie Kleydman said the marathon wasn't important amid all the storm's devastation.
"Look at this," he said, motioning toward the huge piles of discarded furniture and household items that line his street. "Who cares about the marathon? We need garbage trucks, we need FEMA to act quicker. He's worried about the marathon; I'm worried about getting power."
At the midtown New Yorker Hotel, Gisela Clausen of Munich, Germany, told her fellow runners about the cancellation as they walked in.
"You don't understand. We spend a year on this. We don't eat what we want. We don't drink what we want. And we're on the streets for hours. We live for this marathon, but we understand," she said.