A severe, rapidly developing winter storm causes heavy snowfall in the northeastern US today, creating travel problems for millions of Americans, closing schools and wreaking havoc on air travel across the region.

More than 30 million people, from northeastern West Virginia to New England, were issued severe weather warnings as the winter storm swept through parts of the region that saw up to 6 inches of snow during of the night, it was announced by the US Weather Service.

In New York City, the rain turned to snow in the early morning hours. The American metropolis is expected to receive at least 17 cm of snow during the day, making traffic on the roads dangerous.

The rate of snowfall is 5 centimeters per hour in the Lower Hudson, as the New York City Emergency Management Agency reported in a message to X.

“These (snowfall) rates will move further south in the next few hours through midday, soon leading to snow-covered roads and hazardous driving conditions,” the agency said, urging drivers to exercise caution.

Elsewhere in the region, snowfall amounts of up to 30cm are expected before the storm moves further east. In Boston, snow could reach 22cm, prompting the city’s mayor to declare a state of emergency.

Schools across the region have canceled live classes for today, including in New York City, which is teaching remotely for 1 million students.

Meanwhile, more than 900 flights to and from New York’s LaGuardia Airport, Boston’s Logan International and Newark’s Liberty International were either delayed or canceled, according to Flightaware.com.