A nor’easter cyclone hit parts of northeastern United States on Tuesday, forcing New York, New Jersey, Pennsylvania and Virginia to declare emergencies. The National Weather Service has warned around 50 million people living between Pennsylvania and Maine of heavy snowfall by early Wednesday, reported Reuters.

The federal weather agency said that the snowfall may be as much as four inches an hour accompanied with winds blowing at the speed of up to 100 km/hour. Airlines cancelled around 5,500 flights across the US. Newark in New Jersey, LaGuardia in New York and Boston Logan International Airport had the maximum cancellations. Schools across New York City, Washington DC, Boston, Philadelphia and northern New Jersey also called off classes.

The blizzard forced German Chancellor Angela Merkel to postpone her meeting with US President Donald Trump in Washington, reported BBC. The two leaders, who were scheduled to meet on Tuesday, will now hold discussions on Friday.

Weather experts have also predicted that the blizzard can snap power lines and disrupt services. “Everyone along the east coast be safe and listen to local officials as a major winter storm approaches,” said Trump.

Although the blizzard warning has been cancelled for New York, the city still could get as much as eight inches of snow. Governor Andrew Cuomo has already halted above-ground subway services and suspended the Metro-North commuter service to the suburbs. Besides, the government has deployed around 2,000 members of the National Guard and 5,000 plows. “This should be a very serious blizzard, one that everyone should take seriously,” New York Mayor Bill de Blasio said, according to CNN.

Meanwhile, weathermen warned that Boston may get heavy and rapid snow. It could get as much as 12 inches of snow and sleet. A snow emergency was declared in the city, meaning authorities may tow away vehicles parked on road that are marked as snow emergency, reported CNN.

In 2016, New York faced the biggest snowstorm in the city’s history that left 18 people dead. Central Park received a record 27.3 inches of snow in just 24 hours.