Boston - A powerful, fast-moving storm swept through the northeastern US on Thursday, making for a slippery morning commute and leaving some residents bracing for blizzard conditions and more than a foot of snow.Commuters in the densely populated region awoke to windblown snow - less than 24 hours after enjoying spring-like temperatures - and faced slick highways. Forecasters said Thursday's weather had the potential to be the most powerful storm that some areas have seen in a mostly snow-free winter.The National Weather Service predicted that the Boston area and eastern Maine could get 30 to 45cm of snow, and a blizzard warning has been issued for all of Long Island until 18:00. New York City could see 20 to 30cm and the Philadelphia area 12 to 20cm. Near whiteout conditions were possible, with the snow expected to fall at a clip of 5 to 10cm per hour at its peak.Massachusetts activated its emergency management bunker in Framingham, where Gov. Charlie Baker was scheduled to provide updates on the storm at midday. Baker urged people to stay off the roads to allow plows and sanders to do their work.Eastern Long Island was bracing for 30 to 40cm of snow, with a potential for power outages. "The roads are in bad shape ... covered and icy," Suffolk County Police Commissioner Tim Sini said. He said snow was falling at up to 2 inches per hour and expected to intensify as the day went on.New York City Mayor Bill de Blasio said people should stay home."If you need to go out, please, don't use your car," de Blasio said on NY1 television.In Manhattan, intrepid, bundled-up commuters carefully navigated snow-covered sidewalks. The blowing snow stung any exposed skin.Apocalyptic dealSam Lopresti, of Jersey City, New Jersey, warm and dry in his workplace, said he'd been pleasantly surprised that his early-morning train trip to Manhattan had gone smoothly."I fully expected the MTA and PATH to curl into a ball and say, 'Don't hurt me!'" joked Lopresti, an actor and barista.Lopresti said weather forecasts had escalated from "a run of the mill snowstorm to an apocalyptic deal."Officials also are warning of high winds, coastal flooding and possible power outages.New Jersey's emergency management office reported about 50 accidents before midmorning, and that number was expected to grow. New Jersey Transit trains face delays of up to 15 minute.State offices in New Jersey were closed, as were the courts in Massachusetts. Government offices in the Delaware, Bucks, Chester and Montgomery counties surrounding Philadelphia were also shuttered.A number of school systems cancelled Thursday classes including New York City, Philadelphia and Boston. Airlines scrapped thousands of flights by late on Wednesday as a precaution, and FlightAware.com reported 3 323 flights were cancelled on Wednesday through Friday, including more than 2 700 on Thursday.The storm comes a day after much of the Northeast enjoyed a brief glimpse of spring, with temperatures hitting 15°C in some places.Thursday's storm is expected to last 6 to 10 hours, said Carl Erickson, a senior meteorologist with AccuWeather in State College, Pennsylvania.The snow is expected taper off by the early afternoon in the Philadelphia and New York City areas, but New Englanders should brace for snowfall through the evening commute.