New York (CNN) -- New York Mayor Bill de Blasio, who took office 44 days ago promising to bring together residents of a divided city, was widely vilified Thursday for keeping the nation's largest school system open during a brutal storm expected to leave up to 14 inches of snow in some areas.
While millions of children in the region were given the day off, New York City public schools -- with 1.1 million students -- remained open, triggering an avalanche of anger from many students, parents and even one well-known weather anchor.
"It's always a tough decision based on imperfect information," de Blasio told reporters late Thursday morning.
The mayor said the National Weather Service reported as little as 3 inches of snow on the ground at the start of the school day, with warmer conditions than in previous storms. Since 1978, he said, New York City schools have closed due to snow just 11 times.
"At the time," he said, "we thought our children would be able to get to school safely."
On Thursday, attendance in city's public schools was 44.65%.
Gov. Andrew Cuomo declared a state of emergency Thursday for New York City, Long Island and the Mid-Hudson areas.
"These regions are expected to continue to receive heavy snow that may accumulate at rates of around two to three inches per hour, which will make it difficult for plows to keep some roads clear. New Yorkers should stay off of the roads and remain in their homes until the worst of the storm has passed," the governor said in a statement.
On January 3, with only three days in office, de Blasio closed schools when snow combined with frigid temperatures in the first "polar vortex" of the year. But his administration was criticized for not canceling school on other days, including the January 22 storm that brought about a foot of snow to New York.
"There are huge number of parents for whom the consistency of the school schedule is absolutely necessary," de Blasio said. "They are going to work, they have no choice. If they can't get their kid to school, they don't have another option. There are huge numbers of parents for whom their kid getting to school also means their child will have a good meal, and in some cases, two meals. And so, the fact is, it's a very big deal to some parents."
Schools Chancellor Carmen Farina, noting that the snow had mostly stopped in the late morning, said: "It is absolutely a beautiful day."
Many others disagreed with the decision.
"I understand the desire to keep schools open. The only thing that trumps that is safety," Michael Mulgrew, president of the United Federation of Teachers, the city's teachers union, said in a statement. "Having students, parents and staff traveling in these conditions was unwarranted. It was a mistake to open schools today."
The New York City Department of Education's Facebook page exploded with angry comments.
"It was a mistake to open schools and mayor de Blasio and Carmen Farina should be ashamed of themselves for allowing it," wrote Steve Caruso. "It does not show concern for safety it shows stupidity!!!!"
Snookie Cameron wrote: "Maybe Farina should keep the schools open late for the kids to get dinner. It seems that school isn't for an education anymore but only to get food. It is not meals on wheels!!"
Even NBC "Today" show weather anchor Al Roker laid into the mayor on Twitter from Sochi, Russia: "Mr. Mayor, I could never run NYC, but I know when it's time to keep kids home from school."
When asked at the news conference about Roker's comments, De Blasio said: "It's a different thing to run a city than to give the weather on TV," he said amid laughter.
"How about all the parents and caregivers who have to scramble to get their kids home? Is there no one there with common sense?" Roker said in another Tweet. "It's going to take some kid or kids getting hurt before this goofball policy gets changed."
By midday, nearly 10 inches of snow had fallen in Manhattan's Central Park, according to the National Weather Service.
"Are conditions perfect? No, they're not," de Blasio said, adding that basic services were functioning.
In 2013, more than 21 million children nationwide had free or reduced-price lunches, or roughly 70% of the total students who ate school lunches, according to the USDA's Food and Nutrition Service. More than 23 million households received SNAP benefits, known as food stamps, that same year.
"So many families depend on their schools as a place for their kids to be during the day, a safe place where they are not only taught, they get nutrition, and they are safe from the elements," de Blasio said.
CNN's Steve Kastenbaum contributed to this report.