Tornado Damage to the Economy

Worst Tornado Damage Ever

A Tornado
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A tornado is a violently rotating column of air from a thunderstorm that reaches the ground. Tornadoes usually occur east of the Rocky Mountains during the spring and summer. May is typically the worst month.

On average, 800 tornadoes hit a year. They kill 80 people and injure 1,500 more. Since 2008, that average has increased to more than 1,300 injured a year. The most violent tornadoes have wind speeds of more than 250 mph and leave a damage path a mile wide and 50 miles long.

In 2017, there were 1,400 tornadoes. The first quarter was the worst for insurers in 20 years. Tornadoes were a large part of that. There were 425 tornadoes between January and March. That's more than double the 205 tornadoes during the same period in 2016. On average, there were 93 tornadoes in each the first quarters of 2014 through 2016. It's unusual for tornadoes to occur that early in the year. Fortunately, only 35 people died.

The opposite was true in 2018. The first six months saw half the normal amount.

Worst Tornado

The most damaging tornado ever was May 22, 2011, in Joplin, Missouri. It cost $2.8 billion. That's $2.9 billion when adjusted for inflation. It was also the most deadly tornado since 1950. Sadly, 161 people were killed and more than 1,000 were injured. More than 500 businesses were severely damaged, affecting 5,000 workers. 

The EF-5 tornado was one-half mile wide when it touched down in the western part of the city. It expanded to three-fourths mile in width. It traveled 13 miles in all, hitting the City of Duquesne as well. Winds were 200 miles per hour. It traveled about 10 miles per hour.  

Worst Tornado Season

The most damaging tornado season occurred April 25-27, 2011. In that week, 305 twisters hit the Southeast, breaking the 1974 record of 267 tornadoes. The outbreak caused $5 billion in damage. At least two of the storms were EF-5 twisters, producing wind gusts of more than 200 miles per hour.

The tornado outbreak killed 327 people, with 250 dead in Alabama alone. It was the third-deadliest single outbreak in U.S. history. The worst was March 1925, when 747 people died. The second-worst was March 1932, when 332 perished.

That outbreak made April the most active month for tornadoes ever, with 600 tornadoes forming. The previous record was 542 tornadoes in May 2003. It also brought the year's total to 881 tornadoes, almost half the tornado record of 1,817 set in 2004. (Source: Bloomberg, "Deadly Tornado Outbreak May Be Worst in History," May 4, 2011)


Tornado-producing thunderstorms develop in warm, moist air in advance of eastward-moving cold fronts with dry air, known as a "dryline." The United States is the world's "hot spot" for tornadoes, thanks to a combination of a large land mass, called the Great Plains, that warms on hot days; cold, dry wind from the Rockies; and warm, moist air from the Gulf of Mexico. The earth's jet stream swoosh all these together to create Tornado Alley.

The damage from a tornado depends on whether it hits rural or urban areas. The costliest tornado outbreak occurred May 4-11, 2003. At least 100 tornadoes hit eight states, including Kansas City; Oklahoma City; and Jackson, Tennessee. The damage was $3.2 billion. The Sage of Omaha, Warren Buffett, warned that natural disasters pose a greater threat to the economy than terrorism.

Global Warming Affects Tornado Damage

Some say global warming is increasing tornado damage. The Gulf of Mexico is becoming warmer. It increases the contrast when it hits the cold air from the Rockies. But others argue that global warming is reducing the number of tornadoes. They contend the Gulf air warms the cold air from the Rockies, creating less wind shear.

Two separate studies in 2007 reported that climate change could increase the type of weather conditions that feed tornadoes. In the Proceedings of the National Academy of Sciences, Jeff Trapp of Purdue University said the number of days that generate severe thunderstorms could double by the end of the century.

Tony Del Genio, research scientist at the National Aeronautics Space Administration, agrees that tornado activity may be on the rise. Del Genio developed a computer model to research the impact of global warming on tornado activity. According to his research, global warming increases the likelihood of strong updrafts. That's when the wind moves up and down instead of sideways, which is like an incubator for tornadoes. The computer model predicted that global warming would create the conditions most likely to result in the most damaging tornadoes.

 (Source: "Deadly Tornado Outbreak May Be Worst in History," Bloomberg, May 4, 2011.)

Researchers agree that there is a tipping point. If temperatures exceed the Paris Climate Agreement's goal, it will increase the number of tornadoes.

Global warming may be shifting tornadoes eastward, according to a recent study published in the journal Climate and Atmospheric Science. Since 1980, the states east of the Mississippi have experienced more tornadoes while the Great Plains and Texas have seen fewer. That could lead to more death and destruction, since the east is more populated than the west.

Climate change is drying out the Great Plains. Tornadoes breed among thunderstorms that form at the edge of dry and moist air.