STORY: Wind-child warnings were posted for most of New York state and all six New England states - Massachusetts, Connecticut, Rhode Island, New Hampshire, Vermont and Maine - a region home to some 16 million people.

The National Weather Service (NWS) said on Friday the deep freeze would be relatively short-lived, but the combination of numbing cold and biting winds gripping the Northeast would pose life-threatening conditions well into Saturday.

Schools in Boston and Worcester, Massachusetts, New England's two largest cities, were among those closed on Friday over concerns about the risk of hypothermia and frostbite for children walking to school or waiting for buses.

Boston Mayor Michelle Wu declared a state of emergency through Sunday and opened warming centers to help the city's 650,000-plus residents cope with what the NWS has warned was shaping up to be a "once-in-a-generation" cold front.