New York City issued an urgent call for blood donors Wednesday, saying supplies were low after authorities shut down America's largest city for a winter storm that failed to materialize.

"New York City's is experiencing a shortage due to cancellations related to inclement weather," said Mayor Bill de Blasio.

"I urge healthy New Yorkers to help us rebuild our and set aside less than one hour of their time to donate blood—it's not painful... and most importantly, you can help save many lives."

Authorities on Monday banned road travel, and suspended rail and subway services over fears that Winter Storm Juno would dump more than two feet (60 centimeters) of snow in the city of eight million.

Roads opened Tuesday but many businesses remained closed and a majority of commuters spent the day at home as full transport services only resumed Wednesday.

De Blasio has been forced to defend the shutdown as a life-saving measure and meteorologists have apologized for failing to issue more accurate forecasts.

The blizzards instead hit New England, to the north, and Long Island, to the east.