Twin tornadoes bring chaos to New York

Monday 20th Sep 2010 by theWeather Club

New York became America's new 'windy city' this weekend as two tornadoes ripped through the city – wrecking cars and buildings, killing one person and injuring many more.

The storm struck on Thursday evening, and tornado warnings for the region weren't officially taken down until 6pm the following day.

In that time more than 1000 trees were uprooted and thousands of people were left without power, as 100mph winds carved a path of destruction from Staten Island right up through Brooklyn to the Bayside neighbourhood in Queens.

There a falling tree claimed the life of 30-year-old Aline Levakis, who was sitting in her car on the Grand Central Parkway. According to their former business partner Peter Markos, she had just swapped seats with her husband when the tree hit.

Describing the incident as "tragic", New York Mayor Michael Bloomburg said there had been many other stories of people narrowly avoiding the havoc wreaked by trees falling across the city. One resident, Steve Carlisle, likened the sight of a 25-foot branch spinning in the air to "a poltergeist".

"Then all the garbage cans went up in the air and this spinning tree hits one of them like it was a bat on a ball", he told the city's all-news television station NY1.

Where the trees had crashed across front porches and stairways, residents were forced to use axes and chainsaws to force their way out of their homes. Meanwhile tens of thousands of commuters were stranded by delays and cancellations across roads and railway lines.

Emergency crews worked through the night clearing fallen trees from train tracks, freeing trapped motorists and responding to floods of 911 calls.

On Saturday the US National Weather Service confirmed that that the tornadoes had been part of a freak storm, the ninth of its kind to hit the city since 1950 and the second this year. "It's a myth that cities cannot be hit with tornadoes and damaging winds," AccuWeather.com's senior meteorologist and severe weather expert Henry Margusity told The Christian Science Monitor.

Tornados are formed when a thunderstorm starts to rotate, gets hit with wind sheer in the atmosphere and picks up energy from the jet stream. Given the right humidity and temperature, the thunderstorm structure will start to spin all the way down to the surface. When the storm system that had caused tornadoes in Kansas and Ohio accelerated into the east last week, it picked up humidity that was funneling up through New Jersey. At the same time as a cold front was approaching New York, a jet stream was ripping in the region's upper atmosphere.

"All the ingredients came together all at once" says Margusity - and a storm was born.