Sunday 27 April 2014

At least 18 injured after North Carolina tornado outbreak.

At least 18 people have been injured and many more left without homes or electricity following an outbreak of tornadoes on the evening of Friday 25 April 2014. Fifteen of those known to have been injured were in Whichards Beach in Beaufort County, where between 150 and 200 homes were damaged or destroyed by a single tornado, rated 3 on the Enhanced Fujita scale (or an EF-3 tornado). Such a tornado is associated with winds of 218-266 km per hour (61-73 meters per second), and is capable of damaging most ordinary homes. The tornado also left around 2500 people in Beufort County without power.

Damage caused by the 25 April 2014 Wichards Beach tornado. The Outer Banks Voice.

Three people were injured, thirteen homes were destroyed an seventeen badly damaged by three smaller tornadoes (EF1-2) in Pasquotank County, where around 3100 people were left without electricity. In Perquimans County 38 homes were damaged, and 1770 left without electricity. Damage was also suffered by homes in Chowan, Camden and Curritack Counties.

Tornadoes are formed by winds within large thunder storms called super cells. Supercells are large masses of warm water-laden air formed by hot weather over the sea, when they encounter winds at high altitudes the air within them begins to rotate. The air pressure will drop within these zones of rotation, causing the air within them so rise, sucking the air beneath them up into the storm, this creates a zone of rotating rising air that appears to extend downwards as it grows; when it hits the ground it is called a tornado. 

Tornadoes can occur anywhere in the world, but are most common, and most severe, in the area of the American mid-west known as 'Tornado Ally', running from Texas to Minnisota, which is fueled by moist air currents from over the warm enclosed waters of the Gulf of Mexico interacting with cool fast moving jet stream winds from the Rocky Mountains. Many climatologists are concerned that rising temperatures over the Gulf of Mexico will lead to more frequent and more severe tornado events.

Simplified diagram of the air currents that contribute to tornado formation in Tornado Alley. Dan Craggs/Wikimedia Commons/NOAA.

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