TORNADOES AND THEIR DESTRUCTIVE EFFECTS
Even though their times on Earth are short-lived, tornadoes are nature's most violent and destructive atmospheric phenomenon. The are capable of toppling buildings, lifting and rolling mobile homes and automobiles, and hurling people, animals, trees, and debris hundreds of yards in the ait. The United States has the dubious distinction of having the most severe, damaging tornadoes of any country in the world. The combination of moisture, cold air, and strong winds east of the Rockies provide the perfect ingredients for tornado formation. North Carolina is included in the tornado-prone area.
Producing the deafening sounds of roaring jet engines or rumbling freight trains, destructive tornadoes usually travel in a path averaging nine miles in length, ten yards wide, and at speeds ranging from 35 to 45 miles per hour. The can generate violently rotating columns of air with speeds up to 300 miles per hour.
In North Carolina, the most deadly tornado outbreak this century occured on the night of March 28, 1984. The twisters left 44 dead, more than 800 injured, and over $105 million worth of damages.
A tornado usually appears as a funnel-shaped cloud, spinning in a counter-clockwise direction, and extending from the base of a large thundercloud to the ground. They vary from grey to black in color and can bee seen when the air column contains condensation, surface dust, or debris.
Some exceptionally large tornadoes lack the classic funnel shape and may appear as large, turbulent clouds or rain shafts near the ground. Occasionally, two or more tornadoes occur simultaneously, extending from the same thunderstorm.
It is not uncommon for major tornado outbreaks or families of tornadoes to occur during the same period, causing widespread damage over an extensive area, including several states.
One of the nation's worst recorded "outbreaks" -- called the "Deadly Half Dozen" -- the Super Outbreak of April 3-4, 1974, touched down in North Carolina.
Identified as Tornado #148, the last of the family touched down near Baton in Caldwell County. Tornado #121 claimed lives when it struck near Murphy. The storms claimed 315 people as they roared through 13 states.
Strong winds, heavy rain, and especially large hail often precede a tornado and are clear warning signs of impending tornado formation. Large hail stones -- 3/4 inches or greater in diameter -- are often found in that portion of a thunderstorm mass where strong to violent tornadoes are most likely to occur.
Most significant tornadoes come from the southwest and move in a northeasterly direction. They are unpredictable and erratic in behavior -- stationary one moment, and then moving very, very quickly the next. Even though rare, tornado "pathway speeds" of up to 70 miles per hour have been reported.
Through the combined action of stron rotary winds and the impact and speed of airborne debris, tornadoes quickly become a destructive and deadly force. Until recently, it was believed that the drop of atmospheric pressure caused buildings to explode or collapse. The actual cause is the force of the tornado winds pushing the outward wall inward, resulting in the roof being lifted up and the remaining walls falling outward.
What is the most deadly threat of a tornado? Flying debris. The fact is that most tornado-related deaths are caused by head injuries from flying debris. Sticks, glass, roofing materials, lawn furniture, and other similar materials have become dealy missles when driven by the force of a tornado's strond winds. Demonstrating the incredible strength of a tornadoe's wind force, in 1931, a tornado in Minnesota carried an 88 ton railroad coach and its 117 passengers 80 feet through the air and dropped them in a ditch. In 1975, a tornado in Mississippi carried a home freezer through the air for more than a mile.