NOAA's National Centers for Environmental Information
Visit:NCEI U.S. Tornadoes
May 2023 Tornado Occurrences
Source: SPC
According to data from NOAA's Storm Prediction Center, during May, there were 199 preliminary tornado reports. This was below the 1991-2010 average of 276 tornadoes for the month of May. The following paragraphs summarize three notable tornado events through the month.
On May 6-7, there were 24 preliminary tornadoes that impacted several central states clustered across southern Minnesota, northern Missouri and northern Illinois. There were also isolated tornadoes that occurred in South Dakota, Nebraska, Indiana, Kentucky and North Carolina. These tornadoes included (one EF-2, seven EF-1s, four EF-0s and at least four EF-U [unknown intensity] tornadoes). These tornadoes caused scattered damage to homes, businesses, vehicles, agriculture and other infrastructure. There were five reported fatalities and at least eight injuries.
A multi-day tornado outbreak occurred on May 10-13 across areas of the southern and central Plains. In total, there were 113 preliminary tornadoes that impacted eastern Colorado, western Kansas, eastern Nebraska, central Oklahoma and western Iowa. May 12 was the peak day producing the highest count of tornadoes during the month, with 50 preliminary tornadoes reported, many of which were concentrated in eastern Nebraska. These tornadoes included (five EF-2s, 25 EF-1s, 15 EF-0s and at least 33 EF-U [unknown intensity] tornadoes). Among the impacts was one confirmed fatality, several injuries and considerable property damage in Laguna Heights, Texas. One of the Ef-2 tornadoes that impacted Nebraska on the 12th was estimated at nearly a mile wide. These tornadoes included two rated as EF-3s in Oklahoma that caused substantial damage to numerous homes, businesses, vehicles, farms and other infrastructure. Across these four days, there was at least one reported fatality and several injuries.
On May 26-27, there were 19 preliminary tornadoes that impacted several states including Colorado, Wyoming, Idaho, Washington, New Mexico and Texas. These were weaker and isolated tornadoes that caused minor damage to homes, vehicles, agriculture and other infrastructure. There were no reported fatalities or injuries.
Did You Know?
Tornado Count
Final monthly tornado counts are typically less than the preliminary count. This can be due to some phenomena being inaccurately reported as tornadic activity or a single tornado being reported multiple times. Tornado accounts are reported to the local National Weather Service forecast offices who are responsible for going into the field and verifying each tornado reported. This process often takes several months to complete. Once all reports have been investigated, the final count is published by the Storm Prediction Center (SPC).
The Tornado Monthly Climate Reports are written using the preliminary numbers because the final data is not available at the time of production. Historically, for every 100 preliminary tornado reports, at least 65 tornadoes are confirmed. An error bar is depicted on the tornado count graphic representing this uncertainty in the preliminary tornado count.
The following U.S. studies performed by SPC meteorologists offer deeper context and discussion regarding the frequency and distribution of tornado intensity climatologies:
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Edwards, R., H. E. Brooks, and H. Cohn, 2021: Changes in tornado climatology accompanying the Enhanced
Fujita scale. J. Appl. Meteor. Climatol., 60, 1465-1482
DOI: 10.1175/JAMC-D-21-0058.1. - Mccarthy, Daniel & Schaefer, Joseph. (2004). Tornado trends over the past thirty years. paper presented at 14th Conference on Applied Meteorology.