- Education and Science
The Five Most Destructive Tornadoes in U.S. History
What Causes a Tornado?
As a general definition, tornadoes are caused when different temperatures and humidity meet and form thunderclouds. In the United States, most commonly this occurs when warm, wet winds from the Gulf of Mexico move northward and meet colder, dry winds coming south from Canada.
These two opposing weather patterns meet at the dryline. Cool, dry air from the north overrides low, moist air from the Gulf, usually at about 10,000 feet in elevation. The warm air tries to rise, is blocked by the cool air, and as a result the warm air begins to rotate horizontally. As this is happening, the sun continues to heat the Earth’s surface, causing more warm air to try to rise from the surface. Eventually enough warm air is able to break through the colder layer, sending the warm, spinning air upwards. They then rotate faster in this vertical column and can reach speeds of over 200 miles per hour.
The power of nature!
In 1971 the Fujita Scale was introduced as a way of classifying tornadoes. This scale was the brainchild of Tetsuya Fujita of the University of Chicago and Allen Pearson, head of the National Severe Storms Forecast Center.
The Fujita Scale measures a storm’s intensity based mainly on the damage the tornado inflicts on structures and vegetation. It was updated in 1973 to take into account the tornado path and width, and it was replaced in 2007 with the Enhanced Fujita Scale because it was found that damage could occur at lower wind speeds than had originally been thought possible.
Below you will see the Fujita Scale used to measure tornadoes in most of the world, and the damage that can be caused by each level of tornado.
The Levels of Enhance Fujita Scale
Tree damage mostly
roofs peeled off; mobile homes moved
roofs torn off; large trees uprooted
walls torn off; trains overturned
homes leveled; cars and structures moved distances
homes lifted and moved; cars become missiles
very unlikely; total obliteration
The Five Most Destructive Tornadoes in U.s. History
The United States is the capitol of the world when it comes to tornadoes. More than 1200 tornadoes are reported yearly in the United States, four times the number in all of Europe. Tornadoes have occurred in every state in the union since 1950, but most of the tornadoes occur in an area east of the Rockies called “Tornado Alley.” This area includes Nebraska, Kansas, Oklahoma, Missouri, Texas and Iowa.
Some states, such as Alaska, Rhode Island, and Vermont, average one per year, whereas Oklahoma averages 52 per year and Texas a whopping 126 per year. Spring and summer are when the majority of tornadoes are seen, between the months of March and August, but they can occur during any month of the year depending on weather conditions.
Joplin, Missouri Tornado of 2011
The Tri-state Tornado of 1925
On March 18, 1925, an F-5 tornado began in southeast Missouri and with a ground speed of 62 mph made its way northeast to Illinois and Indiana, covering a record 219 miles. This mammoth tornado was between a quarter to three-quarters of a mile wide and over the course of three hours killed 690 people and injured an additional 2,000. In 1925 dollars, the tornado caused an estimated $18 million in damage, equivalent today to $2 billion.
The Lubbock, Texas Tornado of 1970
The city of Lubbock, Texas, home to Texas Tech University, was greeted on May 11, 1970 with an F-5 tornado, the likes of which they had never seen before. When the tornado had finally past the entire downtown district was in shambles. Twenty-eight people died, 500 more were injured, and severe flooding followed immediately. Total damage was in the millions of dollars and included over 1000 homes.
The Waco, Texas Tornado of 1953
At the end of the working day on May 11,1953, downtown Waco was flattened and 114 people were killed by another F-5 tornado. $41.2 million dollars in damage occurred as brick buildings, thought to be impenetrable, were laid to waste by this killer storm.
Two hours prior to that touch-down, the town of San Angelo was hit, leaving 519 homes destroyed, 13 people dead and 159 injured.
The Gainesville, Georgia Tornado of 1936
On April 6, 1936, one of the most destructive tornadoes in history hit Gainesville, Georgia during working hours. Two tornadoes coming from different directions met and formed in Gainesville. This F-4 tornado plowed through a factory and eventually killed 203 people, injuring another 1600, destroyed 750 homes and caused $13 million in damage.
Natchez, Mississippi Tornado of 1840
Before any warning systems had been invented, the city of Natchez was hit completely off-guard by this tornado, killing 317 people and wounding another 109 people. At approximately one p.m. this F-5 tornado hit the busy port city of Natchez and then followed the Mississippi River for several miles, wiping out other villages.
Interestingly enough, most of the fatalities happened to workers on the river and very few to people in homes. Flatboats were picked up by the twister and deposited thirty miles downstream.
One Final Note
The tornado that struck Joplin, Missouri on May 22, 2011 may end up being the most destructive in U.S. history. Final damage totals are not tabulated yet, but the F-5 tornado killed 158 people, injured more than 1,000 more, and caused at least $2.2 billion in damage.
As of the writing of this article, the people of Joplin are still picking up the pieces and trying to recover from this storm.
Other Tornado Facts
Highest winds observed in a tornado: An F-5 tornado on May 3, 1999 in Oklahoma City had winds measured at 301 mph.
Longest damage path and duration: The aforementioned Tri-State Tornado covered 219 miles and lasted 3.5 hours.
Most tornadoes in 24-hour period: April 26, 2011 saw 206 tornadoes during 24 hours accounting for 349 deaths.
Deadliest tornado ever: April 26, 1989, a tornado in Bangladesh killed 1300 people.
Widest damage path: May 22, 2004 in Hallam, Nebraska, a tornado was measured at 2.5 miles in width.
Time to take a poll!
Have you ever experienced a tornado?
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2012 Is Not Over
As far as sheer numbers are concerned, 2012 has been a fairly average year for tornado activity in the United States. The tornado year began on January 9th when a small F-1 touched down in Mission Bend, Texas. So far for the year, 885 tornadoes have been recorded accounting for only 68 deaths.
Despite great advances in technology, there still is no accurate way of predicting a tornado in adequate time to warn citizens. Doppler radar makes it possible to spot supercell storm activity, but where an actual tornado will touch down is still a matter of mystery. The best that is produced to date is a warning that tornadoes are “likely” in any given area.
Until the day arrives when scientists find an accurate warning system, residents in Tornado Alley will continue to look to the skies and cross their fingers in hopes that the “Big One” does not come a’callin’.
Authors note: The 2013 season has gone now, and new destruction rained down on the United States as it did in 2012. More deaths were recorded in Texas, Missouri, Iowa and other midwest states. The early warning systems certainly help but they can never adequately warn us for a funnel cloud that will suddenly appear and create widespread destruction.
2012 William D. Holland (aka billybuc)
"Helping writers to spread their wings and fly."