(CNN) -- Hundreds of thousands lost power due to a potent storm system that extended eastward from the Plains toward the Northeast on Thursday, bringing with it high winds and destructive lightning.
Severe thunderstorm watches were in effect at one point Thursday evening for a continuous stretch from Oklahoma through New Jersey. The danger could lurk for several hours longer, with the National Weather Service issuing such warnings in Delaware, Maryland, New Jersey, Kentucky, Virginia, Arkansas and other points in between.
Well before then, the system had already packed a punch.
In Pennsylvania, a tree crushed a woman in her car as she sought shelter at a campsite, killing her, said Glenn Dunn, the emergency management coordinator for Potter County.
A 61-year-old man in Brooklyn, New York, died after lightning struck a church sending a scaffold crashing down on him, authorities said.
Witnesses reported trees in the region buckling under the impact.
"The trees were bending sideways, (and) the sky just went really dark and green," said Mark Ventrini, a photographer, of the scene around 7:30 p.m. as he headed toward Belmar, New Jersey. "Some of the storms were pretty intense."
The weather service had received reports of possible tornadoes touching down in Elmira, New York, and Brookville, Pennsylvania.
Emergency managers in Broome County, New York, reported people trapped inside a home because of downed trees in the town of Vestal.
Strong storms also caused damage in Binghamton, New York, but the weather service said no injuries or fatalities have been reported.
The residual and more widespread damage came in the form of extensive power outages. More than 100,000 First Energy customers in Pennsylvania, for instance, didn't have electricity as of 10 p.m. ET, with other utilities like PECO and PPL reporting tens of thousands of others similarly in the dark.
An hour earlier, New York Gov. Andrew Cuomo issued a press release stating there were nearly 95,000 customers without power in that state, mostly NYSEG and Central Hudson customers.
Cuomo also declared a state of emergency for hard-hit Chemung County in the southwestern part of the state.
Many more people took in the impressive lightning storms, with daunting bolts preceding booming claps of thunder in small towns and big cities.
"The brunt of the storm itself was intense but short -- there was very strong rain and wind for about 15 minutes, at which point the rain cleared and the lightning show began," said Matthew Burke, a CNN iReporter who photographed lightning sprawling across the New York City skyline.
Several states away, tens of thousands also were in the dark, though power was being restored at a fairly fast rate. AEP Ohio, for instance, reported just over 51,000 customers lacking electricity at 6:15 p.m., yet more than 20,000 of those had the lights back on by 10 p.m.
CNN's Greg Botelho, Lila King, Julie Cannold and Dominique Dodley contributed to this report.