out of the region.

"I want everyone to understand that we are facing -- most likely -- one of the largest snowstorms in the history of this city," said New York City Mayor Bill de Blasio.

He repeated throughout a Sunday afternoon news conference that people should expect delays, very slow or stalled commutes Monday evening. Whatever people do to be cautious, he said, do more.

"My message to all New Yorkers is prepare for something worse than we have seen before. Prepare to be safe. Take every precaution. Now is the time to get ready for this extreme weather," he said. "Don't underestimate this storm."

Photos: Massive storm hammers Northeast Photos: Massive storm hammers Northeast Dexter Newcomb begins cleanup at his house in Scituate, Massachusetts, on Wednesday, January 28, a dayapproaches on January 27. Hide Caption 5 of 38 Photos: Massive storm hammers Northeast Snow piles up at the entrance of a closed T station in Boston on January 27. The city's public transit system was set to reopen the next day. Hide Caption 6 of 38 Photos: Massive storm hammers Northeast U.S. Army soldier Jennifer Bruno carries belongings from her house, center rear, which was heavily damaged by storm surge in Marshfield, Massachusetts. Hide Caption 7 of 38 Photos: Massive storm hammers Northeast Icy water floods a street in Scituate on January 27. Hide Caption 8 of 38 Photos: Massive storm hammers Northeast Snow clings to a man's face as he shovels a sidewalk in Portland, Maine, on January 27. Hide Caption 9 of 38 Photos: Massive