Jul 26, 2008 1:08 pm US/Eastern
How Do They Know It's A Tornado?
EPSOM, N.H. (WBZ) ―
The National Weather Service confirmed Saturday that a tornado struck 11 New Hampshire towns Thursday.
The twister had winds of more than 100 miles per hour, according to an early NWS estimate, making it an EF2 on a scale of 0-to-5.
So how did they figure it out it was a tornado that touched down?
WBZ's Mish Michaels toured the region with investigators Friday morning as they found evidence on two trees that proved it.
Michaels reported there was also evidence of what's known as "straight-line wind damage," which according to the National Weather Service, is "any wind that is not associated with rotation." That evidence is used mainly to differentiate them from tornadic winds.
Straight-line winds are often responsible for most of the wind damage from a thunderstorm. Damage left behind from these winds would leave debris like uprooted trees laid out in the same direction.
However, trees uprooted by a tornado will fall in a different direction, often perpendicular, to the path of the tornado.
"You can see the trees have fallen from right to left, which is a clear indication that the front end of that storm was spinning," said John Jensenius with the National Weather Service. "In this case, a tornado."
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