A Brief History
On April 27, 2011, a mind boggling 216 tornadoes ravaged the United States, from the Midwest to the South to the Northeast, all part of a larger weather phenomenon called the 2011 Super Outbreak that resulted in 306 tornadoes from April 25th to April 28th, 2011. Sadly, 348 people across the US died in the Outbreak, 324 of them from tornado activity and an additional 24 due to related thunderstorm, flash flood and lightning events.
The human carnage was the worst tornado related death toll since 1925, when a stunning 747 Americans were killed on March 18, 1925. Hardest hit in the 2011 Super Outbreak were Alabama and Mississippi, with Alabama alone suffering 238 of the tornado related fatalities. Monetary damage was also severe, costing about $11 billion, one of the costliest natural disasters in US history. Further damage was caused by hail, including hail 4.5 inches in diameter that fell on Virginia! (Hail that big can kill you or destroy your car.)
Under normal weather conditions, the worst sort of tornado, rated EF5 on the Enhanced Fujita Scale (which in 2007 replaced the plain old Fujita Scale that had been introduced by Japanese-American meteorologist Tetsuya Theodore Fujita in 1971), occurs about once per year in the US, but on April 27, 2011, the US suffered the ravages of 4 of the giant tornadoes on the same day. The EF5 rating for a tornado indicates windspeed of over 200 mph (322 kph for metric minded people) and extreme damage caused. (“Extreme Damage” defined as “Strong-framed, well-built houses leveled off foundations are swept away; steel-reinforced concrete structures are critically damaged; tall buildings collapse or have severe structural deformations; some cars, trucks, and train cars can be thrown approximately 1 mile (1.6 km).”)
What is a tornado? A tornado is a rapidly rotating column of air that is in contact both with the ground and either a cumulonimbus or (rarely) a cumulus cloud. Often visible due to the condensation, dust and debris sucked into the circling winds, a tornado typically gives the impression of a funnel shaped cloud moving across the ground, twisting and turning as it goes. Not all tornadoes are visible. Most tornadoes are of less than 110 mph and only travel a few miles before they dissipate. The usual width of these common tornadoes is only about 250 feet.
Monster tornadoes are a different story. The worst of them have wind speeds of 200 to 300 miles per hour and can be 2 miles wide, laying a path of destruction for many miles, perhaps as much as nearly 60 miles! A tornado over a body of water creates a phenomenon called a “water spout,” something to avoid by those on a boat. Other names for tornadoes include twister, cyclone, and whirlwind. (Cyclone is both a colloquial term for tornado and a scientific term used by weather scientists for specific weather conditions that are not tornadoes.)
Question for students (and subscribers): Have you ever seen a tornado? Have you witnessed the damage caused by a tornado? Feel free to share any tornado related stories you may have in the comments section below this article.
Your readership is much appreciated!
For more information, please see…
Roker, Al. Al Roker’s Extreme Weather: Tornadoes, Typhoons, and Other Weather Phenomena. HarperCollins, 2017.
Verkaik and Verkaik. Under the Whirlwind: Everything You Need to Know About Tornadoes But Didn’t Know Who to Ask. Whirlwind Books, 2001.