How fast does ice falling from NYC rooftops go? Faster than you think.

"If a 10-pound sphere of ice about 10 centimeters in diameter were to fall, he said, "very quickly" - in about three seconds - "it would reach a terminal velocity of close to 50 or 60 mph." "You're talking about being potentially hit by something 10 pounds going 50 miles an hour. Uh, not pleasant.""

""I would judge about 40 feet maybe," Moscatelli said - roughly four or five stories. "Not much." That means even mid-rise buildings can pose a risk if ice accumulates along parapets or ledges."

"The same wet, packable snow that made for easy snowmen and snowball fights is also clinging stubbornly to rooftops, window ledges and scaffolding across the five boroughs. As temperatures hover around or above freezing by day and dip into the 20s at night, that snow can melt, shift and refreeze into slabs of ice."

Following a recent winter storm, New York City faces a significant hazard beyond slippery sidewalks: accumulating snow and ice on buildings. The wet, packable snow sticks readily to rooftops, window ledges, and scaffolding across the five boroughs. As temperatures fluctuate between freezing during the day and dipping into the 20s at night, this snow melts, shifts, and refreezes into ice slabs. In NYC's tall urban landscape, even small ice chunks become dangerous projectiles. A 10-pound sphere of ice can reach terminal velocity of 50-60 mph in approximately three seconds, requiring only about 40 feet of fall—roughly four to five stories. This means mid-rise buildings pose significant risks, with falling ice capable of causing substantial damage to vehicles and infrastructure.

Read at Gothamist