Violent Outbursts Of Wind & Rain: Tornadoes

By WBNG Weather

July 22, 2010 Updated Jul 14, 2010 at 12:34 PM EDT

However terrifying they might be, tornadoes are among the most fascinating of weather anomalies. An average of 850 twisters touch down in the United States each year, yet they are uncommon enough to be newsworthy wherever they appear. Their tightly wound vortices, usually measuring less than a few hundred feet across, are mysterious and unpredictable performers of strange and destructive achievements.

In photographs, tornadoes can be beautiful. But you’ll hear many witnesses that have seen the same cloud up close and personal say that tornadoes are terrifying. Witnesses have described tornadoes as sounding like freight trains, a B-52, dog’s howling, a million bees, or the booming of a thousand cannons.

A number of complex conditions must be met before a tornado can form. The first necessity is a mesocyclone: a column of riding warm air that rotates because of conflicts in speed and direction of winds at various altitudes. The rotation may begin as a horizontal spin, like a tube rolling along the ground, caused by strong winds blowing over weaker ones. If the tube of rolling air is picked up by a powerful updraft, the horizontal rotation can convert to vertical rotation strong enough to start the entire storm rotating. As it rotates, additional warm air is sucked into the rising column of air with enough force to create updrafts up to 100 miles per hour for thousands of feet to the top of the thunderstorm.

Once a tornado develops, the spinning air causes atmospheric pressure to drop in the center of the funnel. As the pressure drops the air expands and cools, causing the moisture within it to condense into a visible funnel cloud. A “pure” tornado is often white, but it will turn gray, black, or brown as it picks up dirt and debris from the ground and as the clouds above it are drawn downward.

The National Weather Service in Binghamton, NY has confirmed a tornado in Windham Township in Bradford County of Pennsylvania on June 22, 2010. The tornado touched down at approximately 8:30 PM with an Enhanced Fujita Scale Rating of EF1. The estimated wind speeds were up to 105 mph with a path width of 250 yards and a path length of 1.7 miles.

The tornado first touched down on Osbourne Hill Rd. in Northeast Windham Township around 8:30 PM. Numerous trees were uprooted and snapped as the tornado tracked along Osbourne Hill Road east toward Route 187. The heaviest damage was to a hillside close to where Osbourne Hill Rd. meets Rt. 187. Over 100 trees were snapped and uprooted on this hillside. The tornado then crossed Rt. 187 and uprooted and snapped trees along Huddle Road. One house had numerous trees down on the property with one tree falling on the back of the house. Some minor roof damage was also done to this house. A camper was also flipped on Huddle Rd. The tornado then tracked up a hillside east of Huddle Rd. and lifted. The good news is that nobody was injured!

For reference, the Enhanced Fujita Scale classifies tornadoes into the following categories.

EF0...WIND SPEEDS 65 TO 85 MPH.
EF1...WIND SPEEDS 86 TO 110 MPH.
EF2...WIND SPEEDS 111 TO 135 MPH.
EF3...WIND SPEEDS 136 TO 165 MPH.
EF4...WIND SPEEDS 166 TO 200 MPH.
EF5...WIND SPEEDS GREATER THAN 200 MPH.

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