Three dozen people or more were killed over the weekend as powerful storms raged across the south-central United States. At least thirty-six people have been reported to have died and dozens more were injured after at least 23 tornadoes were reported in Missouri, Arkansas, Oklahoma, Texas, Kansas and Mississippi. Missouri in particular was hit hard by the storms, with up to 19 tornadoes that affected 25 counties.

Damage consistent with EF4 tornadoes were reported in places, with winds estimated at 190 miles per hour. The Enhanced Fujita scale, abbreviated as EF scale, rates tornado intensity based on the severity of damage caused. Starting with EF0, defined as tornadoes having winds of 65-85 miles per hour and causing light damage, the numbers on the scale progressively increase to EF4, with winds of 166-200 miles per hour and causing devastating damage, and EF5, with winds above 200 miles per hour and causing catastrophic damage.

In addition to the tornadoes, high sustained winds with gusts of up to 80 miles per hour were reported throughout the region, causing semi-trucks to be blown off of roads and increasing the danger of wildfires in areas that have recently experienced such outbreaks.

One fire, near Fredericksburg, Texas, about 75 miles west of Austin, expanded from about 400 acres to over 8,600 acres on Saturday. Smoke from this fire was visible in Austin. Fires are also reported in north Texas, Oklahoma, Kansas and Mississippi. Red Flag warnings, indicative of conditions in which fire dangers are high, cover large areas of these states, as well as in Colorado, Nebraska, Wyoming, and South Dakota. Fires were the cause of several deaths in Oklahoma, and a total of 142 fire-related injuries have been reported in the state.

A dust storm caused a major traffic accident on Interstate 70 near the Kansas-Colorado border in which 71 vehicles were involved. At least 8 people are reported to have died in this incident, in which visibility dropped to nearly zero. The highway was not cleared of wreckage for nearly 24 hours. In Oklahoma and Texas, four people were killed in multiple crashes; one multi-vehicle crash near Blackwell, Oklahoma that involved an ambulance saw multiple injuries, including two paramedics. Further to the north, this same storm system caused blizzard conditions.

The storms moved further to the east, leaving destruction in north Georgia, including the Atlanta area. Other areas threatened include Jacksonville, Florida, all the way north to Erie, Pennsylvania.

While tornadoes can form in the southern US throughout the year, spring is the period when the most form. Peak tornado activity generally occurs in May. It is not unusual for storms to form in March; indeed, the worst tornado disaster in US history happened almost exactly 100 years ago, when one tornado killed 695 people through Missouri, Illinois and Indiana.

The period of peak tornado activity is moving earlier. During the 1970s, this shifted from mid-June to the last quarter in May. This trend appears to be continuing; April of 2024 was the most active April since 2011. 

What is also changing is the number of storms that spawn multiple tornadoes. The number of days in which there is a tornado somewhere has been decreasing, but the number of tornadoes that form on those days has been increasing. Thus, the annual average number of tornadoes reported has remained generally unchanged, but within this there is evidence of change. In a report issued last year, Harold Brooks, a senior research scientist at National Oceanic and Atmospheric Administration’s National Severe Storm Laboratory, said that climate change could be affecting tornado behavior. As global temperatures increase, there is more available energy for storms. More moisture and instability in the atmosphere create the storm systems in which tornadoes form.

Another indication of changing tornado behavior is the creation of more tornadoes during the cooler part of the year, November through early March. The energy that causes thunderstorms in which tornadoes form has traditionally not been present during these months.

Climate change may also be expanding the geographic area known as “tornado alley,” where these storms have most commonly formed. Many of the places where tornadoes are forming have higher populations than in previous periods. Parts of the southeastern US, such as Alabama and Mississippi, have more densely populated rural areas than the plains states which have traditionally had higher numbers of tornadoes. More tornadoes in these areas will naturally result in greater death and destruction.