By Adam Fenster

ELMIRA, N.Y., July 27 (Reuters) - Two people were dead and more than 100,000 homes and businesses in New York, Ohio and Pennsylvania were without electricity Friday morning after severe thunderstorms swept through the region late Thursday.

The storms spawned a tornado that touched down in Elmira, New York, toppling trees and tearing off roofs, the National Weather Service said.

Officials in Pennsylvania and New York reported two storm-related deaths.

A woman who was camping in Genesee, Pennsylvania, near the New York State line, was killed when she took refuge from the storm in her car and a tree then fell on it, John Hetrick, director of emergency services for Potter County, said.

In New York City, 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., police said.

"It's possible that lightning struck the top of the roof, causing some bricks to fall on top of the scaffolding, causing the scaffolding to fall on top of the victim," a police spokesman said.

In Elmira, the city's east side took the biggest hit from the tornado. In one four-block neighborhood, most homes had trees toppled upon them, street signs were bent in half and tree trunks had debris wrapped around them. Several cars were crushed by downed trees.

One two-story brick building had most of the second story torn off in the storm.

On Friday morning, most power remained out for the city's 29,000 residents.

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 rolling across some cities, hail ranging from the size of a dime to a quarter fell in some areas of Pennsylvania, AccuWeather.com said.

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 Northeast into the Ohio Valley, bringing the threat of damaging winds, hail and tornadoes, according to the Weather Channel.

The storm activity 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. (Additional reporting by Kevin Gray and Alex Dobuzinskis; Writing by Dan Burns; Editing by Eric Walsh)

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  • Clouds gather over apartment buildings a

    Clouds gather over apartment buildings ahead of a thunderstorm on the east side of Manhattan July 26, 2012 in New York. AFP PHOTO/Stan HONDA (Photo credit should read STAN HONDA/AFP/GettyImages)

  • Derecho!

  • Scary clouds over New York City!

  • Pedestrians pass an umbrella vendor during heavy rains in Times Square, Thursday, July 26, 2012, in New York. The storm resulted in more than 20,000 customers without power in the Elmira area in upstate New York, where buildings were damaged, power lines and trees toppled, and hospitals placed on disaster status after a possible tornado hit the city Thursday afternoon. (AP Photo/John Minchillo)

  • Storm clouds loom over Times Square as Manhattan braced for heavy weather, Thursday, July 26, 2012, in New York. The storm resulted in more than 20,000 customers without power in the Elmira area in upstate New York, where buildings were damaged, power lines and trees toppled, and hospitals placed on disaster status after a possible tornado hit the city Thursday afternoon. (AP Photo/John Minchillo)

  • Pedestrian's umbrellas buckle under high winds as a massive storm loomed above Times Square, Thursday, July 26, 2012, in New York. The storm resulted in more than 20,000 customers without power in the Elmira area in upstate New York, where buildings were damaged, power lines and trees toppled, and hospitals placed on disaster status after a possible tornado hit the city Thursday afternoon. (AP Photo/John Minchillo)

  • Clouds gather over an apartment building

    Clouds gather over an apartment building ahead of a thunderstorm on the east side of Manhattan July 26, 2012 in New York. AFP PHOTO/Stan HONDA (Photo credit should read STAN HONDA/AFP/GettyImages)

  • Storm clouds move overhead in the Bronx

    Storm clouds move overhead in the Bronx July 26, 2012 in New York. A severe thunderstorm warning is in effect in the New York City area. AFP PHOTO/DON EMMERT (Photo credit should read DON EMMERT/AFP/GettyImages)

  • Storm clouds move overhead in the Bronx

    Storm clouds move overhead in the Bronx July 26, 2012 in New York. A severe thunderstorm warning is in effect in the New York City area. AFP PHOTO/DON EMMERT (Photo credit should read DON EMMERT/AFP/GettyImages)

  • Clouds gather over apartment buildings a

    Clouds gather over apartment buildings ahead of a thunderstorm on the east side of Manhattan July 26, 2012 in New York. AFP PHOTO/Stan HONDA (Photo credit should read STAN HONDA/AFP/GettyImages)

  • Storm clouds move overhead in the Bronx

    Storm clouds move overhead in the Bronx July 26, 2012 in New York. A severe thunderstorm warning is in effect in the New York City area. AFP PHOTO/DON EMMERT (Photo credit should read DON EMMERT/AFP/GettyImages)

  • The storm roles in...

    <a href="http://www.huffingtonpost.com/social/Lynda_Lippin"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1049069807/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Lynda_Lippin">Lynda Lippin</a>:<br />From my apartment on the 22nd floor of New York by Gehry. (Copyright 2012 Lynda Lippin).

  • The Jersey Shore

    <a href="http://www.huffingtonpost.com/social/redeemer609"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/aol_profile_img/2950717.png" /></a><a href="http://www.huffingtonpost.com/social/redeemer609">redeemer609</a>:<br />

  • Ghostbusters Cloud

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  • summer storm

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  • Near Derecho UWS looking toward Central Park 7:30pm

    <a href="http://www.huffingtonpost.com/social/Lulbrownbear"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/Lulbrownbear">Lulbrownbear</a>:<br />

  • Calm Before the Storm

    <a href="http://www.huffingtonpost.com/social/artsychick53"><img style="float:left;padding-right:6px !important;" src="http://i.huffpost.com/profiles/2840753-tiny.png?20120714103204" /></a><a href="http://www.huffingtonpost.com/social/artsychick53">artsychick53</a>:<br />Springfield, NJ - Right before the storm hit.

  • Miller Place, NY

    <a href="http://www.huffingtonpost.com/social/dpo7124"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/dpo7124">dpo7124</a>:<br />The wall approaches.

  • Adrien Hobbs - Derecho -

    <a href="http://www.huffingtonpost.com/social/Adrien_Hobbs"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/657544774/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Adrien_Hobbs">Adrien Hobbs</a>:<br />Lightning Strikes Chrysler Building Skyline

  • East Harlem

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  • East Harlem

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  • Stormy Hells Kitchen

    <a href="http://www.huffingtonpost.com/social/Robert_Sammons"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1540184511/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Robert_Sammons">Robert Sammons</a>:<br />Storm over Hells Kitchen

  • Ghostbuster Cloud - Chrysler Building - Adrien Hobbs

    <a href="http://www.huffingtonpost.com/social/Adrien_Hobbs"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/657544774/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Adrien_Hobbs">Adrien Hobbs</a>:<br />

  • storm clouds over North Wildwood 07/19/2012

    <a href="http://www.huffingtonpost.com/social/craftieqte"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/aol_profile_img/3648358.png" /></a><a href="http://www.huffingtonpost.com/social/craftieqte">craftieqte</a>:<br />Looked like something out of War of the Worlds ...rolled in and out in 20 minutes

  • storm clouds over North Wildwood 07/19/2012

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  • storm clouds over North Wildwood 07/19/2012

    <a href="http://www.huffingtonpost.com/social/craftieqte"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/aol_profile_img/3648358.png" /></a><a href="http://www.huffingtonpost.com/social/craftieqte">craftieqte</a>:<br />

  • storm clouds over North Wildwood 07/19/2012

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  • Storm Clouds Gathering

    <a href="http://www.huffingtonpost.com/social/Matthew_Angell"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1536933913/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Matthew_Angell">Matthew Angell</a>:<br />Long Island NY

  • Central Park North

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  • storm clouds over North Wildwood 07/19/2012

    <a href="http://www.huffingtonpost.com/social/craftieqte"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/aol_profile_img/3648358.png" /></a><a href="http://www.huffingtonpost.com/social/craftieqte">craftieqte</a>:<br />

  • Storm Clouds Gathering

    <a href="http://www.huffingtonpost.com/social/Matthew_Angell"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1536933913/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Matthew_Angell">Matthew Angell</a>:<br />Long Island NY

  • storm clouds over North Wildwood 07/19/2012

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  • Shades of Gray

    <a href="http://www.huffingtonpost.com/social/StarliteStarBright"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/StarliteStarBright">StarliteStarBright</a>:<br />Storm clouds gather over Manhattan. As seen from Fort Lee, NJ

  • Storm in Jersey

    <a href="http://www.huffingtonpost.com/social/mbc2915"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/mbc2915">mbc2915</a>:<br />Storm on Jersey Shore

  • Storm Cloud of Darkness

    <a href="http://www.huffingtonpost.com/social/NeonParrot04"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/NeonParrot04">NeonParrot04</a>:<br />"And then the room went black." The Cure--