EF5 tornadoes: rare but deadly

HORRY COUNTY, SC (WMBF) – EF5 tornadoes are the rarest of tornadoes, but by far, the most deadly. They have winds in excess of 200 miles per hour and can wipe out entire communities within seconds.

EF5 tornadoes, like the one that struck Newcastle and Moore, Oklahoma on Monday, are very rare and make up only .01 percent of all tornadoes, according to the National Oceanic and Atmospheric Administration.  The United States averages approximately 1,000 tornadoes each year, 95 percent of which are typically rated lower than EF3. In a given year, only about 20 tornadoes can be expected to be "violent," or EF4 and only one can be expected to be "incredible"- rated EF5.

Although EF5 tornadoes only happen about .01 percent of the time, they result in the most fatalities; some estimates say as much as 90 percent of all tornado deaths in United States history are the result of F5/EF5 tornadoes. The EF5 tornado that struck Joplin, Missouri on May 22, 2011, was the most deadly tornado in the U.S. since 1974, directly killing a total of 158 people.

On May 3, 1999, a significant tornado outbreak affected portions of the central plains, including one tornado that struck the southern suburbs of Oklahoma City, including the city of Moore. This tornado is perhaps one of the most studied tornadoes of all time, as it would go down in history as one of the most violent tornadoes ever recorded. As the tornado passed over Bridge Creek, Oklahoma, around 6:54 p.m., a Doppler On Wheels mobile Doppler radar detected winds of over 300 miles per hour inside the tornado at about 35 yards above ground level. The tornado caused over $1 billion in damage, killed 36 people and injured 295.

The Carolinas certainly receive their fair share of severe weather, but luckily, neither of the Carolinas have ever experienced a documented F5/EF5 tornado. However, between 1950 and 2011, the state of North Carolina has been hit by twelve F4/EF4 tornadoes, and South Carolina has been struck by ten F4/EF4 tornadoes. In fact, during the famous 1984 Carolinas tornado outbreak, two F4 tornadoes struck Bennettsville in Marlboro County. The first tornado in Bennettsville dissipated on the north side of the town; another F4 tornado touched down minutes later, near where the previous tornado left off. It then traveled into Scotland, Robeson, and Cumberland Counties before ending. Combined, the two tornadoes killed 11 people and caused nearly 500 injuries.

Tornadoes are rated on the Enhanced Fujita Scale based on the damage they cause to well-built structures. Based on the damage the tornado causes, meteorologists can estimate the wind speed of the tornado. For a tornado to be rated EF5, according to the Enhanced Fujita Scale, strong frame houses must be completely leveled and swept away from their foundations. For this damage to occur, scientists estimate that wind speeds need to be at or greater than 200 miles per hour. 

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