2025 has already been an above average year for tornadoes, which have had significant and deadly impacts in many communities in the United States.
The strongest tornadoes:
Tornadoes are usually destructive and dangerous, but the strongest on the Enhanced-Fujita scale: EF4 or EF5 are also called violent. These tornadoes generate winds over 166 miles per hpur (267kph) and can toss cars, sweep solid homes from their foundations, and devastate structures.
What happened this year so far:
So far this year, there have been almost 900 confirmed tornadoes in 30 states, which have laid waste to landscapes and killed dozens of people. This is happening against the backdrop of a government administration that is slashing the staff that maintains and disseminates the nation's weather prediction and warning systems.
The number of tornadoes this year has exceeded the ten year average. In the past decade, zero to six EF4 tornadoes have happened every year since 2015, making an average of three per year. But there have been five in the US already in 2025. Two EF4 tornadoes hit Arkansas on March 14, and the next day, a tornado that moved from Tangipahoa Parish, Louisiana, to Covington County, Mississippi reached EF4 speeds. There were another two on May 16 in Illinois and Kentucky.
The last EF5 tornado in the US struck Moore, Oklahoma, near Oklahoma City on May 20, 2013.
Where do tornadoes usually happen?
Tornadoes can occur wherever conditions are right, but they happen most often in North America because of the continent's geography and topography, which leads to a collision of air masses. Warm and wet air from the Gulf of Mexico streams north as cool, dry air pushes east over the Rockies. These masses have tended to collide around northeastern Texas and Oklahoma, promoting the formation of tornadoes in the region.
Most violent tornadoes have happened around here in the past, with Oklahoma, Texas, Iowa and Kansas seeing the most violent tornadoes. But the humid Gulf air is now pushing farther east, and the tornadoes are following.
How do tornadoes form?
Tornadoes always form in supercell thunderstorms, but not all supercells make tornadoes. An unstable atmosphere that holds warm air near the ground and dry, cold air above it can generate supercells. The warm air pushes upward because it is more buoyant. Wind sheer, in which winds change direction and speed as height increases, can lead to the formation of a horizontally rotating air tube. Finally, an updraft can tighten and accelerate this rotation, Ohio State University tornado researcher Jana Houser, explained to Scientific American.
Even with these conditions, a tornado does not always form. “Most supercells don’t even actually produce tornadoes in their lifetime,” Houser added. We still have more to learn about the ingredients that produce tornadoes.
During Spring, there is an abundance of cold air from northern latitudes while the south is heating up; the conditions for a tornado are more likely during this time of year.
Sources: The Weather Channel, Scientific American