Deadly tornadoes in the United States: Why is the center of the country particularly affected by this phenomenon?

Kentucky and Missouri in mourning. Violent tornadoes struck these two central US states on Friday, May 16, killing at least 20 people . Significant damage was particularly noted in the large city of St. Louis, a city with a population of 300,000, in eastern Missouri.

This region of the United States is regularly hit by these violent tornadoes . Missouri, in particular, is located in "Tornado Alley," a corridor that stretches from South Dakota to Texas and where 30% of the tornadoes that sweep across the United States form—several hundred each year.

To understand why tornadoes are so fond of this area, you need to know how they form. These swirling columns of air, which can reach speeds of over 400 km/h, often originate at the base of immense storm clouds, cumulonimbus clouds, explains our journalist Anthony Ferry in the BFMTV podcast La question météo climat .

To form, tornadoes require warm, moist air near the ground and cold, dry air aloft. When these two air masses meet, they create atmospheric instability that can lead to tornado formation. The Tornado Alley states combine these conditions. The Gulf of Mexico provides a constant source of warm, moist air, while cold air masses descend from Canada.

Kentucky, on the other hand, is more of a "Dixie Alley" state, an area also prone to swirling winds but more in the southeastern United States.

In 2024, tornado-related accidents killed 54 people in the United States, according to the National Oceanic and Atmospheric Administration (NOAA).

In France, the north of the country, as well as Brittany, Charente, and the Mediterranean region, are classified as high-risk for tornadoes . These regions have low relief, stormy conditions throughout the year, and are particularly exposed to disrupted airflows. These are all ingredients necessary for the formation of these meteorological monsters.