Just a few weeks after the National Weather Service downgraded the May 31, 2013 El Reno, Oklahoma tornado from EF-5 to EF-3, a research paper published this week suggested that this tornado may be the largest most powerful (note that I say powerful, not destructive) tornado ever recorded, having been upgraded from 2.6 to 4.3 miles wide. Yes, 4.3 miles wide. The tornado can be seen in the graphic below (each square is 1 mile by 1 mile).
May 31, 2013 El Reno Tornado on Radar, from KFOR
When compared to the two Moore tornadoes on May 3, 1999 and May 20, 2013, as well as the 2011 Joplin tornado, the numbers can be hard to get your head around. The May 3, 1999 Bridge Creek/Moore tornado has long been the bar set for maximum tornado power and destruction. It was pretty clear that the 2011 Joplin tornado and the 2013 Moore tornado eclipsed the May 3rd tornado as far as damage and destruction go, but neither came close to the power of the May 3rd twister. I will let the following table tell the tale.
Doppler radar data from the mobile radar trucks also apparently shows that the subvorticies inside the El Reno tornado, which are essentially mini-tornadoes embedded in the larger circulation of the main tornado (often referred to as a multi-vortex tornado), were up to a mile wide. Let me put that into perspective for you. The subvorticies inside the El Reno tornado were essentially the width of both the May 3rd and the Joplin tornado. The exact strength of these subvortices is still unknown at this time.
Interestingly enough, the only other well-documented tornado that comes close to the width of the El Reno tornado also occurred on May 3, 1999, which struck the town of Mulhall, Oklahoma. This tornado was not as destructive becuase it did not strike a major population center, but the numbers are still very impressive.
It will be very interesting to see what else is uncovered as these tornadoes are studied further, and what changes are made in response to it. I will pass along the information as it comes in, so stay tuned.
See also: Why the May 31st El Reno Tornado was Downgraded to EF-3