Climate conditions significantly influence both minor activities, like a fishing trip on the weekend, and major ecosystems, such as the health of fisheries. For example, temperatures above the normal range may cause algal outbreaks, commonly known as “red tides.” In other areas, unseasonably warm weather have the potential to produce tornadoes—intense vortexes of air that usually emerge from thunderstorms and touch down to the earth. Under severe circumstances, these powerful phenomena can wreak havoc on structures and infrastructure, overturn vehicles effortlessly, and create lethal flying debris — and they’re beginning to affect a wider geographical area of the US than ever before.

While scientists are still researching the impact of climate change on tornado occurrences in the U.S., there is growing evidence that global warming is making extreme weather events more frequent or more intense. With February 2024 being the third-warmest February on record, Americans living in areas routinely impacted by tornadoes will need to be vigilant during the 2024 tornado season.

U.S. Tornado Intensity Over Time

While tornado occurrences regularly top 1,000 each year, over 80% of them are considered light or moderate.

Tornado formation requires atmospheric energy—typically from warm, unstable air out of the Gulf of Mexico—and significant wind shear—or changes in wind speed and direction between the ground and atmosphere. And although high-intensity tornado occurrences have the potential for more destruction, the vast majority of tornadoes in the U.S. are considered light or moderate.

“Weak” tornadoes—those rated EF0 or EF1 on the Enhanced Fujita (EF) Scale—accounted for 83.3% of all tornado occurrences in 2023 and topped 80% every year since 1989. High-intensity tornadoes, or those rated EF2 or higher, were much less frequent. EF2 (13.0%) and EF3 (3.5%) tornadoes were the next most common occurrences, while there were only two EF4 and no EF5 occurrences in 2023.