How tornado severity is determined
To determine the strength of a tornado, the National Weather Service created the Enhanced Fujita Scale or EF-Scale. The EF-Scale takes into account 28 damage indicators including building type and degree of damage, trees downed, etc. Based on this information, storm experts can also estimate wind speed. The categories range from EF-U (no damage) and EF-0 (light damage) all the way up to an EF-5 (incredible damage).This scale replaced the original Fujita scale in 2013. The original Fujita scale had been used since 1917.
There have been almost 60 storms classified as an F5 or EF-5 (depending on what scale was used when they occurred) from 1950 to the present[3].
Tornadoes are also measured in terms of their deadliness and how many people were killed as a direct result of the storm. Another measure of tornado damage is the estimated cost to repair the damage caused. For this article, we’ll look at both the five deadliest storms and five most damaging (which incidentally have no crossover).
Deadliest tornadoes in U.S. history
These five storms caused the greatest loss of life.
1. The Tri-State Tornado
On March 18, 1925, the deadliest single tornado in the history of the United States occurred. The enormous storm affected people in Missouri, Illinois and Indiana, hence the name. As a result, almost 700 people were killed and over 2,000 were injured. The storm destroyed more than 15,000 homes and caused $1.4 billion in property damage (adjusted for inflation)[4].
2. Tupelo-Gainesville Outbreak
While technically more than one storm, in April of 1936 an outbreak of tornadoes killed more than 450 people. This is the only outbreak where two seperate tornadoes resulting from the same storm outbreak each killed more than 200 people. The storms largely impacted people in Tupelo, Mississippi and Gainesville, Georgia[5].
3. The Great Natchez Tornado
On May 7 ,1840, the second deadliest tornado in the U.S. hit Natchez, Mississippi. It caused over 300 people to lose their lives. One of the reasons the storm killed so many is because it not only hit Natchez, which sits along the Mississippi River, but also swept across the river sinking many of the flatboats carrying freight and their crews[6].
4. The 1896 St Louis Tornado
On May 27, 1896, a historic tornado swept through St Louis, which was one of the larger and more influential inland cities in the U.S. at the time. The result was catastrophic loss of life and infrastructure. The storm killed at least 255 people and caused around $352 million in damages (adjusted for inflation) in about 20 minutes[7].
5. The Joplin Tornado
Jumping ahead in history, on May 22, 2011, a devastating multiple vortex tornado struck Joplin, Missouri. The EF-5 tornado was nearly one mile wide and cut a path through the city damaging 8,000 buildings. Sadly, over 150 people were killed and over 1,000 were injured[8].
Most damaging tornadoes in U.S. history
While not as tragic as a loss of life, these five storms left the greatest monetary amount of damage in their wake.
1. The Joplin Tornado
This is the only storm to make both lists. In addition to the number of casualties, damages from this tornado reached $2.8 billion. It resulted in the largest insurance payout in Missouri history.
2. Tuscaloosa-Birmingham Tornado
Like the Joplin tornado above, this storm occurred in 2011 (which incidentally was a rough year for tornadoes as this storm was one of 360 in the 2011 Super Outbreak). The EF-4 multiple-vortex tornado swept through Tuscaloosa and Birmingham, Alabama leaving significant destruction in both cities. The storm led to $2.4 billion in damages. It would remain the costliest tornado in U.S history for almost a month until the Joplin storm happened[9].
3. Moore Oklahoma Tornado
Just two years later in 2013, an EF-5 tornado (as of 2023, the last tornado to strike the U.S. that was so rated), touched town in Moore, Oklahoma. The storm destroyed an estimated 1,150 homes and caused damages of around $2 billion[10].
4. Tornado Outbreak in Dallas
In October of 2019, an outbreak of tornadoes affected the Dallas/Fort Worth Metroplex. One of the storms, rated an EF-3 did extensive damage to a suburb of Dallas, making it the costliest tornado event in Texas history. The resulting damage was around $1.55 billion dollars. Combined the 10 tornadoes in the outbreak caused damages closer to $2 billion[11].
5. Bridge Creek-Moore Tornado
Back on May 3, 1999 a powerful F5 (predating the EF scale) tornado registered the highest wind speeds ever measured globally. The tornado affected portions of Oklahoma City and surrounding towns. One town affected was Moore, which you may remember from up the list, would be yet again struck fourteen years later. Adjusted for inflation, damages from this tornado were around $1.5 billion[12].