A man walks his dog across a slush and snow covered street in the Park Slope section of Brooklyn, New York February 14, 2014. [Photo/Agencies]

NEW YORK - People in US cities facing one of the most brutal winters on record have been dealing with something far more dangerous than snow: ice falling from skyscrapers.

Several streets around New York's new World Trade Center, the nation's tallest building, were closed Wednesday morning when wind-blown sheets of dagger-shaped ice hit the pavement near the 1,776-foot (541-meter) structure.

Frightened pedestrians ran for cover. The streets reopened by midafternoon.

Around the country, sidewalks around high-rises in cities have been cordoned off with yellow caution tape because of falling icicles and rock-hard chunks of frozen snow. Experts warn it could get worse over the next few days as a thaw sets in over much of the country.

"The snow starts to melt and the liquid drips off and makes bigger and bigger icicles, or chunks of ice that break off skyscrapers," said Joey Picca, a meteorologist at the National Weather Service in New York, which has had 48.5 inches (1,230 millimeters) of snow since the start of the year.

Some architects say newer, energy-efficient high-rises may actually be making the problem worse.

"They keep more heat inside, which means the outside is getting colder and that allows more snow and ice to form," said engineer Roman Stangl, founder of the consulting firm Northern Microclimate in Cambridge, Ontario.

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