Weather researchers at Iowa State University say a shifting climate and warmer ocean temperatures are partially responsible for a record number of tornadoes this spring.

More than 100 were reported in Iowa, in May alone.

Eleven hundred tornadoes were reported regionwide in May from Texas to Minnesota and from West Virginia to Georgia. That’s more than twice the 30 year average.

One of the fiercest killed five people and injured dozens in rural Greenfield Iowa.

ISU Severe Weather Meteorologist and Professor of Meteorology William Gallus said extreme heat from a changing climate has increased ocean temperatures and is one contributing factor to this year’s storms.

“Mexico and Texas were having record high temperatures” said Gallus. “That was allowing the Gulf of Mexico to rapidly warm up get much warmer than normal which means that is our main source of energy.”

Gallus said the weather pattern known as El Nino characterized by warmer ocean temperatures that prompt more precipitation and provide fuel for severe weather is now shifting to La Nina marked by cooler seas and drier weather.

That could cause the rest of the tornado season to be less active.

Gallus said the high number of tornadoes in the region was unusual since climate change models predict Iowa and neighboring states west of the Mississippi should being seeing below average numbers which they have in recent years.

“The long-term trend has been for tornadoes to be hitting more places east of the Mississippi River” said Gallus.

Gallus said data show tornadoes occurring on fewer days each year but coming in clusters and with greater intensity.

He says some storms that have been listed as Category F3 are probably F5’s but measurement methods in some areas are not adequate to gauge the storms’ intensity.

In a recent study, weather researchers at Iowa State University have linked a record number of tornadoes this spring to shifting climate patterns and warmer ocean temperatures. A staggering 1,117 tornadoes were reported from January to May across regions from Texas to Minnesota and West Virginia to Georgia, which is more than double the 30-year average. Iowa alone saw over 100 tornadoes in May, with one particularly severe tornado in Greenfield, Iowa, resulting in five fatalities and numerous injuries.
Professor William Gallus, a Severe Weather Meteorologist at ISU, attributed the increased tornado activity to extreme heat, particularly in Mexico and Texas, which has led to unusually warm Gulf of Mexico waters, a key energy source for these storms. The weather pattern El Nino, characterized by warmer ocean temperatures and increased precipitation, has fueled severe weather but is now transitioning to La Nina, which typically brings cooler seas and drier conditions. This shift may result in a less active tornado season for the remainder of the year.
Despite the recent uptick, Gallus notes that long-term climate models predict fewer tornadoes in Iowa and neighboring states west of the Mississippi River, a trend seen in recent years. However, tornadoes are becoming more intense and occurring in clusters on fewer days annually. Some storms, initially categorized as F3, may actually be F5s, but current measurement methods are inadequate to accurately assess their strength.