Violent thunderstorms barreled through the Ohio Valley and mid-Atlantic regions of the eastern United States late on Thursday, killing two people and cutting power to more than 130,000 homes and businesses in New York, Ohio and Pennsylvania.
The storms spawned at least one tornado, which touched down in Elmira, New York, toppling trees and ripping off rooftops, the National Weather Service said.
Officials in Pennsylvania and New York reported two storm-related deaths.
A woman camping in Genesee, Pennsylvania, near the New York state line, took refuge from the storm in her car. She was killed when a tree fell on the car, said Potter County emergency services director John Hetrick.
New York City police said a 61-year-old man in Brooklyn's Cobble Hill neighborhood was killed when scaffolding at a church collapsed on him as the storm passed through near 8 p.m.
He was identified as Richard Schwartz, a longtime assistant attorney general in New York who was at the forefront of investigations involving such high profile targets as Microsoft and the National Football League.
"It's possible lightning struck the top of the roof, causing some bricks to fall on top of the scaffolding," said a police spokesman.
The storms forced the cancellation of over 900 flights on Thursday, according to FlightAware, a Texas-based company that tracks the status of flights. The highest number of cancellations was at LaGuardia Airport in New York.
The one reported tornado hit Elmira's east side hardest. In one four-block neighborhood, most homes had trees toppled on them, street signs were bent and tree trunks had debris wrapped around them. Several cars were crushed by downed trees.
One two-story brick building had most of its second story torn off in the storm, and most power remained out for the city's 29,000 residents on Friday morning.
Meteorologists said 70-mile-per-hour (113-kph) winds were reported in parts of Ohio, Kentucky, Pennsylvania and Oklahoma.
As the storms sent black, menacing clouds across cities and open country, hail ranging from dime- to quarter-sized fell in some areas of Pennsylvania, AccuWeather.com said.
By midday Friday, utilities across the region had made only modest progress in restoring power, with more than 130,000 homes and businesses still without electricity.
Pennsylvania accounted for a majority of those still without power, with more than 85,000 customers in the dark early Friday, according to electric companies serving the region.
Roughly 34,000 people in New York were without power, most of them in the southern-tier region near Elmira, according to NYSEG. About 13,500 customers in eastern Ohio were still offline, according to AEP Ohio.
The storms formed along a cold front stretching from the Ohio Valley into the northeast, bringing the threat of damaging winds, hail and tornadoes, according to the Weather Channel.