WASHINGTON, Feb 13 — A powerful winter storm that iced streets and downed power lines across the US South moved toward the Northeast with heavy snow and sleet, threatening to cripple air and ground travel.

The storm may bring 20cm to 30cm of snow to New York City and more to its northern and western suburbs starting early tomorrow, the National Weather Service said. Philadelphia might get 25.4cm and Washington, 20cm.

An additional 2.794cm of ice is forecast to coat Atlanta before the storm ends there.

“It is pretty nasty” in the South, said Tom Kines, a meteorologist with AccuWeather Inc. in State College, Pennsylvania.

“They should probably just close everything and not start opening things up until Monday. I just cannot imagine what it’s like down there. There’s nobody on the roads and there shouldn’t be any.”

Across the US, 3,291 flights were canceled as of 4:26pm today, including more than two-thirds of all arrivals and departures at Hartsfield-Jackson Atlanta International Airport, said FlightAware, a Houston-based tracking service.

An additional 3,113 flights were scrubbed for tomorrow. JetBlue Airways Corp. dropped 36 per cent of its schedule for tomorrow.

Travel Curtailed

Highways across Georgia were closed because of icing and downed power lines, including US 1, according to the state’s Department of Transportation website. Traffic slowed to a crawl in Charlotte and Raleigh, North Carolina, as people tried to make their way home in the snow.

Amtrak said it would cut back on the number of Acela and Northeast Regional trains it runs between Boston and Washington and suspended some trips into the South. Ten traffic deaths in the region were blamed on the storm, the Associated Press and state officials said.

About 410,000 homes and businesses from Arkansas to North Carolina were blacked out as of 4pm New York time, according to utility websites. That included 240,000 customers in North Carolina and 133,000 in Georgia.

An ice-storm warning was posted from eastern Alabama to South Carolina calling for as much as three-quarters of an inch. In addition, a Civil Emergency Message ordering motorists off the roadways was issued for South Carolina, the weather service said.

“Possibly historic ice accumulations of over 1 inch of ice will be possible for portions of northern Georgia and South Carolina, with a little over half an inch of ice possible for central North Carolina,” said the US Weather Prediction Center in College Park, Maryland.

Atlanta Scene

In Atlanta, where schools closed yesterday, the city’s usually busy roads were clear and its buses halted because of the storm. The Metropolitan Atlanta Rapid Transit Authority was sending some buses into the streets to act as warming shelters, according to its website.

Lows overnight in Atlanta and Columbia, South Carolina, will reach -1.6º Celsius, the weather service said

Philadelphia Public Schools canceled classes for tomorrow, the system’s website said.

Snow will begin tonight in Washington, where Federal Reserve Chairwoman Janet Yellen postponed tomorrow’s testimony before Congress, and start in Boston about dawn, Kines said.

In New York, snow showers will start in the city after midnight and then become heavier through the morning, said Joe Pollina, a weather service meteorologist in Upton, New York.

“By the time commute time comes around, we may see some moderate to heavy snow falling across the area,” Pollina said.

NYC Outlook

Rain and sleet may mix in with the snow throughout the day before changing back to all snow, he said. In northern New Jersey, it’s possible 25cm to 35cm will fall.

Flat roofs, trees and power lines are in danger from new snow dropping atop any left over from last week, Pollina said. On Feb. 3, 20cm fell in Central Park.

So far this year, the park has received 105.41cm, or 65.532cm more than the 30-year average of 39.878cm, according to weather service data.

The storm’s track and speed will determine how much snow the large cities of the Northeast get, said Kines. Forecasters know that the snow will change to rain, however, exactly when that happens can’t be pinpointed.

“At the time or near the changeover time, the precipitation is going to be coming down pretty hard, so any delay in the changeover can mean 5cm or 7cm more,” Kines said.

“If it changes over earlier, you can get 5cm or 7cm less.” — Bloomberg