Wild weather grounds 900 flights

SEVERE thunderstorms unleashed heavy rain and strong winds across the US, grounding hundreds of flights and leaving tens of thousands of people without power. 
There were over 900 flight cancellations on Thursday, according to FlightAware, a Texas-based company that tracks flights. 
The highest number of cancellations was at LaGuardia Airport in New York. 
Flight delays were also reported at airports in Baltimore, Boston, Chicago, New York City, Philadelphia and Washington D.C., the Federal Aviation Administration said on its website.
The storms spawned a tornado that touched down in Elmira, New York, damaging a mall and a local country club, the National Weather Service said. 
There were no immediate reports of injuries. Forecasters warned of potentially destructive winds gusts in some areas of up to 112 km/h. 
As the storms sent black, menacing clouds rolling across some cities, hail fell in parts of Pennsylvania, said AccuWeather.com. 
More than 51,000 customers were without power in Ohio, said American Electric Power of Ohio. 
New York Governor Andrew Cuomo said in a statement that the storms knocked out power for nearly 93,700 utility customers across the state. 
The storms formed along a cold front stretching from the Northeast into the Ohio Valley and threatened damaging winds, hail and tornadoes, according to the Weather Channel. A severe thunderstorm watch was issued for portions of Indiana, Kentucky, Maryland, New York, Ohio, Pennsylvania and West Virginia. Thunderstorms that swept through Westchester County, north of New York City, toppled trees and caused power outages.