Written by Tony Olson
Illustrated by Sneh Boro
On May 20, 2013, an extremely powerful EF5-rated tornado struck the city of Moore, Oklahoma, taking 24 lives and injuring many more¹. Since 2007, tornadoes have been rated on the Enhanced Fujita (EF) scale, with a zero being the weakest and a five being the most powerful. Any tornado over an EF3 is considered violent, making up about 2% of all reported tornadoes in the United States². After the 2013 Moore EF5, there were no reported EF5 tornadoes for 12 years. This streak would finally break on June 20, 2025, when an EF5 hit Enderlin, North Dakota³. The odds of this happening were calculated by National Severe Storms Laboratory researchers Anthony Lyza, Harold E. Brooks, and Mackenzie Crocak to be about 0.3%⁴. This begs the question: why did the drought last so long, and what exactly was different about the Enderlin tornado to warrant an EF5 rating?
In the United States, or globally?
The EF5 drought has been a subject of debate over the past decade among meteorologists. Theories range from global warming affecting tornado strength to a government conspiracy of purposefully lower ratings ensuring lower insurance payouts. However, the common consensus is that the EF scale has simply evolved over time as the National Weather Service (NWS) grew more accustomed to its use⁴. Therefore, the criteria for an EF5 tornado have become significantly stricter, resulting in no tornadoes reaching the threshold between Moore and Enderlin. The main reason for this is one specific damage marker — damage to buildings. For an EF5 rating, a well-built construct must be completely destroyed. However, most tornadoes don’t strike many structures, such as the 2013 El Reno EF3, which received that ranking despite being the largest tornado on record⁵. Others don’t hit any structures that are sturdy enough to be considered as an EF5 damage marker, which occurred with the 2023 Rolling Fork EF4⁶.
In the case of Enderlin, the defining factor wasn’t a building at all. The tornado picked up an empty train car and threw it 475.5 feet — a feat that required wind speeds of 210 miles per hour — and also tipped over several fully loaded cars³. However, this damage wasn’t considered until months later. Initially, the NWS gave the Enderlin tornado a rating of EF3. It wasn’t until October 6, almost four months later, that it would be upgraded to an EF5. Comparatively, the Moore tornado received its final rating on May 21, 2013, just a day after the actual tornado¹.
This change in timeline reflects a change in the methodology of rating tornadoes. This event shows the NWS gradually using more forensic analysis in ratings, which results in tornado ratings changing retroactively over a significant period. This is something that the meteorological community has been pushing for some time, though many assumed it would never happen. The common belief was that there would never be another EF5, and the next maximum rating of tornado would only come with the advent of a new rating system. This does not make up for all the shortfalls of the EF system, though, which considers damage to buildings, towers, poles, and trees, but not to vehicles or ground scarring⁷. The EF scale continues to be updated to this day, which, along with this change, will hopefully result in more tornadoes like Enderlin receiving an accurate rating.
Sources:
- US Department of Commerce, N. (2023, May 20). The tornado outbreak of May 20, 2013. National Weather Service. https://www.weather.gov/oun/events-20130520
- US Department of Commerce, N. (2025, February 24). Violent tornadoes. National Weather Service. https://www.weather.gov/lmk/violent_tornadoes#:~:text=Tornadoes%20that%20are%20intense%20enough,two%20percent%20of%20all%20tornadoes.
- pdf. National Weather Service. (2025, October 6). https://www.weather.gov/media/fgf/Enderlin.pdf
- Lyza, A. W., Brooks, H. E., & Krocak, M. J. (2025). Where have the ef5s gone? A closer look at the “drought” of the most violent tornadoes in the United States. Bulletin of the American Meteorological Society, 106(8). https://doi.org/10.1175/bams-d-24-0066.1
- US Department of Commerce, N. (2024b, February 26). The May 31-June 1, 2013 tornado and flash flooding event. National Weather Service. https://www.weather.gov/oun/events-20130531
- US Department of Commerce, N. (2024c, April 25). Extended severe event of March 24-27, 2023. National Weather Service. https://www.weather.gov/bmx/event_03242023
- US Department of Commerce, N. (2024a, January 31). The Enhanced Fujita Scale (EF scale). National Weather Service. https://www.weather.gov/oun/efscale