Clarification of El Reno Tornado Width Claim

It has come to my attention that the tornado width ascribed to the El Reno tornado in my previous post is not quite accurate.  On the topic, Josh Wurman writes,

“That is a ridiculous interpretation, out of context, of the observation that the width of 30 m/s winds at >100 m AGL sometimes extended for about 7 km and that the equivalent 50 m/s width was as wide as 5 km.  How those correlate to expected surface damage is unknown.  The paper has a long footnote saying that using these definitions as ‘width’ is very subjective.  The diameter of the large circulation was about 2 km, very large, but similar to other Multiple Vortex Mesocyclones (MVMC) that we’ve documented before.”

I believe the confusion lies in the definitions contained within the conference paper.  In the paper, Wurman seems to equate the multiple-vortex mesocyclone (MVMC) with the tornado itself, noting that an interior sub-vortex was “nearly concentric with the larger tornado / MVMC”  (Wurman et al. 2013, AMS Radar Conference).  The slash would seem to indicate the interchangeability of the terms “tornado” and “MVMC”.  However, this is not the case.  In an early online release of the BAMS article of this work, it is clear that the 7 km (4.3 mi) width is ascribed to the parent circulation, not the tornado.  My previous post has been edited to reflect this understanding.

Regardless, the 2.6 mile width will remain in the record books, according to the National Weather Service.

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About Gabe Garfield

I am a research meteorologist from Norman, Oklahoma. In addition to my work, I am interested in storm chasing, sports, philosophy, theology, and culture.
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5 Responses to Clarification of El Reno Tornado Width Claim

  1. This issue is a really thorny one, harkening back to my web essay about how to define a tornado. In many cases, it’s relatively straightforward, but as I discussed in my essay, when you have a ‘mesocyclone’ producing damaging winds at the surface, how do you make the distinction? I like to say “All the atmosphere does is produce vortices of various sizes and intensities. What we choose to call them is our problem, not the atmosphere’s.” What we have is the classic taxonomy problem, but taxonomies are for humans and have little or no basis in the real world.

    On top of the classification dilemma, the whole notion of tornado ‘width’ is a nightmare … where does “damage” begin and end? Was the observed damage from the winds or from debris impacts? Driving back and forth across the Moore tornado path made it pretty evident to me that the lateral boundaries along a tornado damage path are pretty ill-defined! If we had radar-based velocities, we certainly could use the diameter of the winds above a certain threshold (presumably around 50 knots, where “damaging” winds begin in the definition of a severe storm). It seems to me that tornado widths in the climatological record are not very well-defined and ‘consistent’ from one event to the next!

    • Thanks for your input, Chuck – it’s much appreciated!

      This is a very messy process indeed! During the El Reno damage survey, I would say it was darn near impossible to find a consistent width (which is why called on OU RaXPol for help).

      And, of course, width is only one issue with the tornado database. As we’ve discussed (ad nauseum), there are hosts of inconsistencies in the record. Thus, as you’ve mentioned before in your blogs, “consistency” seems to be a poor argument against using good data.

  2. I really don’t know much about tornados, but I have always been fascinated. I did realize how hard it is to classify and characterize tornados like these. I was reading about the peak wind speed in this tornado, and it seems there is still come debate about the 296MPH peak measured by OU RaXPol. What do you think of that measurement?

    • Hi Christian,

      I think the OU RaXPol data is very good. The real debate is whether or not you should include radar measurements in tornado ratings. That debate continues…

      Gabe

  3. fethy says:

    THANKS YOU FOR THIS CLARIFICATION of TORNADO ,i live in europe ,we have not the tornado

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