Severe thunderstorms, lightning and hail transformed a perfectly sunny morning in New York and adjacent Tri-State area on Tuesday to a dark and gloomy day, within minutes, with residents hurrying to seek shelter.

National Weather Service office of New York warned people to “SEEK SHELTER NOW inside a sturdy structure and stay away from windows,” issuing a severe storm warning as well as a flood advisory that was supposed to stay in effect till 11 p.m. EDT. 

In addition to those, a possible tornado warning was issued for Dutchess, Orange, Sullivan and Ulster counties in New York and Fairfield County in Connecticut.

With the sudden worsening of the weather, many people took to social media to see whether New York too, like Washington D.C. on Monday, had been hit by a derecho.

According to Accuweather, “Derechos are often referred to as inland hurricanes due to the hurricane-like conditions, in terms of ferocious wind and torrential rain, which are spawned by this weather phenomenon… These violent severe thunderstorm clusters produce widespread and long-lived, straight-line wind damage.”

These type of devastating storms differ from a tornado or a hurricane in that its wind system travels wide and fast-moving, causing wind damage for more than 250 miles, in a straight-line, rarely changing direction. Gusts of wind under a derecho can reach more than 58 mph, according to Vox

Stephen Corfidi, a researcher at the University of Oklahoma’s Cooperative Institute for Mesoscale Meteorological Studies, said derechos are generally very difficult to predict as they form quickly in small scales. Most of the derechos sweep over the central United States between the months of May and August.

Although the weather service is yet to confirm whether people of New York experienced a derecho on Tuesday, the severity of the weather did bring panic among residents and wide-spread property damages in the Tri-State area. People from New York took to social media after witnessing lightning that sounded like a bomb explosion:

Winds traveling at winds of 65 to 78 mph battered the Hudson Valley, while heavy rain, accompanied by hail the size of baseballs showered down on the area.

New York Gov. Andrew Cuomo declared a state of emergency in Dutchess, Orange, Putnam, and Sullivan Counties due to the severe weather, and deployed 125 members of the state’s National Guard to aid in damage control.

The Grand Central Terminal was temporarily suspended after reports of multiple trees being downed onto the lines. Thousands of commuters were left inside the terminal without transport during rush hour. Fallen trees and flooding also caused delays at the Port Authority Bus Terminal, ABC7 reported. 

Grand Central Terminal Commuters wait for train service to be restored after a severe thunderstorm downed trees that caused power outages resulting in several Metro-North lines being suspended at Grand Central Terminal in New York City, May 15, 2018. Photo: Getty Images/ Eduardo Munoz Alvarez

An 11-year-old girl was seriously injured when a tree fell onto the vehicle she was in, traveling in. She was trapped inside the car and had to be rescued. The girl did not survive.

Danbury Mayor Mark Boughton said a Connecticut man who was mowing the lawn when the storm hit and who took shelter in his truck, was killed when a tree fell on the vehicle, Reuters reported.

In Mahwah, New Jersey, a tree crushed a garage, destroying a car worth $100,000.