I will admit right off that I did no research on the information provided here. The information was taken from the blog of research meteorologist, Gabe Garfield. It was impressive enough to pass on.
Data on the El Reno, Oklahoma tornado of May 31, 2013 was released at a recent weather radar conference. It was nothing short of amazing, and I have little doubt now that the tornado has set the bar for extreme events. Colorado recently was hit by an extreme flood event, one that is estimated to occur only once in 1000 years. Could it be possible that the El Reno tornado was a once in a 500-1000 year event?
Gabe wrote (with minor edit):
* Near Highway 81, the El Reno tornado achieved a peak forward motion of 55 mph!
* After the tornado crossed Highway 81, the sub-vortices within the larger circulation grew to mammoth proportions. The largest were bigger than the size of 3 football fields!
* As the tornado approached Highway 81, small vortices developed on the northwest side of the circulation and “fed” the circulation.
* The tornado displayed vortices on multiple scales. This “tornado within a tornado” behavior was noted shortly before the tornado crossed Highway 81. At that time, the tornado had two prominent vortices: an inner vortex, about 150 yards in width, and an outer vortex about 1.25 miles in diameter.
* One of the most intense sub-vortices during the tornado translated at an incredible 180 mph! Curiously, it was also stationary at times during its two minute life-span.
* At 6:26 p.m., the Doppler on Wheels measured a 255 mph gust in a sub-vortex just south of I-40. This exceeds the EF5 threshold by over 50 mph.
* In addition to the gigantic cyclonic tornado, the El Reno storm simultaneously produced a strong anti-cyclonic tornado. This tornado featured powerful sub-vortices with winds peaking around 145 mph!
The above data was gathered from a paper titled “Preliminary Results from the ROTATE-2013 Season”
With authors: Joshua Wurman, Karen Kosiba, and Paul Robinson (Center for Severe Weather Research, Boulder, Colorado) and Tim Marshall (Haag Engineering)