After weeks of engineering analysis, informed largely by a new technique developed by Western's Canadian Severe Storms Laboratory (CSSL), a tornado that hit Enderlin, N.D. this summer has been officially rated EF5 by the U.S. National Weather Service, the highest category on the Enhanced Fujita Scale (EF).
This EF5 tornado is the first of its kind in the U.S. since the Moore, Okla. tornado in 2013 and ties the EF wind speed record with the 2011 El Reno, Okla. tornado.
This historic rating was made possible through the application of cutting-edge research by engineers and scientists at the Northern Tornadoes Project (NTP), which provided the scientific foundation for confirming wind speeds exceeding 338 km/h.
"This case exemplifies the importance of integrating engineering analysis and scientific research into operational meteorology," said Connell Miller, director of the Northern Mesonet Project and former NTP wind impacts researcher. "Our work demonstrates that extreme wind events can be reliably assessed using forensic evidence to improve wind speed estimates in tornadoes."
The Enderlin tornado derailed 33 train cars, including multiple fully loaded grain hoppers weighing about 129,700 kg each. (Brian Emfinger)
Devastating winds
A violent tornado tore through southeast North Dakota on June 20, 2025, leaving a 19.5 km path of devastation up to 1.7 km wide. Initial assessments by the National Weather Service suggested high-end EF3 damage but lacked sufficient EF Scale damage indicators to justify a higher rating.
The Enderlin tornado derailed 33 train cars, including multiple fully loaded grain hoppers weighing about 129,700 kg each. One empty tanker car, weighing roughly 32,600 kg, was lofted more than 145 metres from the tracks.
To estimate the wind speeds required to cause this level of displacement, experts applied findings from a peer-reviewed study led by Miller, published in the journal Monthly Weather Review in 2024.
This novel research established that lofting large compact objects more than 50 metres generally indicates EF5-level winds. In Enderlin, a fully loaded tanker car (nearly four times heavier than the heaviest object modeled in the Miller study) was thrown almost three times farther than the EF5 threshold distance.
Calculations on the Enderlin train car confirmed wind speeds well exceeding the EF5 threshold. These findings were instrumental in confirming the tornado's EF5 rating, despite the absence of traditional EF Scale damage indicators.
"The National Weather Service's use of this research underscores its significance for future tornado assessments, offering a powerful new tool for rating storms that produce extreme yet unconventional damage," said Miller. "CSSL and NTP remain committed to advancing tornado science and supporting operational meteorology through innovative engineering methodologies."
