Chris Martin walks his Great Dane, Sydney, in his North Druid Hills neighborhood of Atlanta on Sunday afternoon. It was Sydney’s first experience with snow. A powerful March snowstorm blanketed much of Alabama and then marched across Georgia on Sunday, forcing some flight cancellations in Atlanta. The East Coast braced for a potential pummeling amid winter storm warnings.

Birmingham, Ala. ? A potent March snowstorm blanketed much of the Southeast with snow Sunday before barreling toward the Northeast, where officials prepared snowplows and road-salt for a wintry assault.

The icy blast threatened to drop up to a foot of snow in the Philadelphia area, 13 inches in New York and 15 inches across southern New England late Sunday.

Thousands of New York City sanitation workers prepared to salt city streets, and airlines pre-emptively canceled flights Sunday at the region’s major airports.

The Pennsylvania Department of Transportation planned to attack the snow in the Philadelphia area with 400 trucks and 77,000 tons of stockpiled salt, assistant press secretary Gene Blaum said.

In Georgia, the snowfall rendered roads treacherous and delayed flights, while in Alabama, more than 210 churches in the central part of the Bible Belt state had to cancel morning services.

Vonda Braswell of Alabaster, Ala. was throwing snowballs in her front yard instead of putting on her Sunday best. “I think you can worship in this it’s so rare,” she said.

Up to 7 inches of snow was expected through this morning in areas of Maryland, northern Virginia and Washington, D.C., where Mayor Adrian Fenty declared a snow emergency.

In Virginia, nearly 10,000 customers of two power companies lost electric power Sunday night after the storm blew in.

Maryland has already spent more than $40 million responding to bad weather in what’s been a colder-than-usual winter, Gov. Martin O’Malley said Sunday. Any money spent on digging out from the rare March storm will further burden a state that’s facing a $2 billion budget shortfall.

“I don’t like snow,” O’Malley said.

In New York, Mayor Michael Bloomberg an-nounced more than 1,300 sanitation workers stood ready to spread salt and plow streets.

“It’s the first of March, which as you know is the month that we say comes in like a lion and out like a lamb,” he said. “It’s pretty clear that the lions are getting ready to roar.”