2013: May 31 El Reno, OK EF-5 is Widest Tornado On Record

[Jason Harris]

A historical day for sadder reasons already, but interesting to know of this width record.
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The National Weather Service has just upgraded the May 31 El Reno, Union City tornado to an EF-5 with a width of 2.6 miles wide, making it the widest tornado ever documented.

http://kfor.com/2013/06/04/update-el-reno-union-city-tornado-widest-tornado-on-record/


Reed mentions in that video linked above that the rapid broadening grew from under a mile to 2.6 in about 30 seconds. Combine that with the erratic movement, traffic problems, and it's no wonder it was a terrible day for chasers.
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He said the tornado was moving east/southeast, when it hit Highway 81 and made a sharp 120 degree turn to the northeast and accelerated.

"It was moving an average 25-35 mph, and it turned and accelerated to 40-45 mph," Laubach said.

Tim Samaras founded TWISTEX (Tactical Weather Instrumented Sampling of Tornadoes Experiment) and invented probes that measured wind velocity, pressure drops and other data.

"Tim made scientific history with the TWISTEX Probe, jokingly referred to as “the turtle" because of its shape. By deploying these probes into a tornado’s path, Tim, along with Carl, provided key data for researchers studying the storm’s movements and deadly force. The information collected has directly resulted in increased warning time for local authorities to tell residents to take cover," said Eileen O'Neill, president of Discovery Network.

http://www.thedenverchannel.com/new...aras-carl-young-was-ef-5-widest-ever-recorded

 

[Hannah.Taylor]

I read on Reed's facebook that it went from a mile wide wedge to 2.6 miles in 30 seconds which comes out to expanding at the rate of 180 mph (don't ask me, I saw another chaser say that, but I suck at math!). Definitely makes things difficult to escape from under those circumstances.


Previously the widest tornado on record was Hallam, NE in 2004 @ 2.5 miles wide. That's just insanity in terms of sheer size..what's next? 3 and 4 mile wide tornadoes? My God.

 

[Kevin Franz]

I think this puts everything in perspective and no longer feel there is anything anyone could have done to prevent this other than not chasing that day. There are many other threads talking about the authorities blocking roads etc. being an issue. While I agree, it sounds like there were some poor decisions, I no longer think they had a direct impact on the results. Tim and Paul Samaras and Curt Young sadly lost their lives doing exactly what they set out to do, seeing the most amazing supercells/tornados possible. And as it happens this was the largest and quite possibly the most dangerous, ever recorded, somewhat fitting. May their souls rest in peace, as from what I understand no one did it better.

On a side note, the Hallam, NE tornado is the event that made me become a storm chaser. A friend and I were ridiculous that night and thought we'd leave Lincoln to go find the storm. Long story short, we ended up having to pull over in what were some of the strongest winds I've ever experienced, still to this day, and ride out the storm. As it turned out we were less than a mile away from the impact at Norris Highschool. We were idiots and had not a clue of what we were doing. I swore from that time forward I would never be uneducated and in that position again. El Reno, OK has served as another reminder for me to be safe, educated and aware at all times. And hope that is enough.

 

[Shawn Schuman]

I read on Reed's facebook that it went from a mile wide wedge to 2.6 miles in 30 seconds which comes out to expanding at the rate of 180 mph (don't ask me, I saw another chaser say that, but I suck at math!). Definitely makes things difficult to escape from under those circumstances.


Previously the widest tornado on record was Hallam, NE in 2004 @ 2.5 miles wide. That's just insanity in terms of sheer size..what's next? 3 and 4 mile wide tornadoes? My God.

Depending on how you define a tornado's width, I suppose. Check Mulhall, OK from 5/3/99.

 

[Mike Peregrine]

I was also on the Hallam storm and when a storm becomes that large and powerful, there is really no way to distinguish between mesocyclone and tornado. They are both one and the same as the entire meso appears to reach down to the ground. I have a video grab as the storm was moving through Hallam where you can't distinguish between tornado and the rest of the storm base. There must be some mechanism behind this phenomena that isn't fully explained by conventional thinking concerning tornadogenesis. Most large wedge tornadoes are actually multivortex which are wrapped in a larger field of circulation and it's amazing how quickly two or three vortices can come together into something much bigger. We saw this on the Glen Elder tornado in 2008 too and I believe we also saw it briefly in Concordia on 5/29/04 ... I'm sure people who are still actively chasing have seen it a lot more often than when I did back when I chased.

Seems reasonable for it to be predominately associated with HP storms which have access to ridiculous amounts of moisture close to the surface, and the storm enters some sort of strengthening phase as everything maxes out for a bit. I doubt that any storm could sustain a tornado of that size for any prolonged length of time as it requires an incredible amount of energy to generate (as in, more than a lot of atomic bombs are capable of). On days like last Friday or on May 22, 2004, it makes sense to stay well away from under the meso altogether. Of course, I feel that should always be the case.

As a side note here, I have no idea how you would go about distinguishing a tenth of a mile in terms of diameter when a tornado is this big.

 

[Brian McKibben]

I just got this image off of twitter. 4km away from the center. I wonder how they got that bad boy packed up and out of the way so fast.

Gabe Garfield ‏@gabegarfield3h
@amosmagliocco Yes - it was directly measured since the radar was ideally located to get both vortex speeds (i.e., to the ENE at ~4 km)

 

[STexan]

I saw that truck there and wondered "damn, they're pushing they're luck a bit" but I'm glad they were there to provide some nearby information backup

 

[Jason Harris]

Where does Shawn's example of Mulhall fit in with the current criteria exactly?
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The widest tornado as measured by actual radar wind measurements was the Mulhall (1999) tornado in northern Oklahoma which occurred during the 1999 Oklahoma tornado outbreak. A Doppler On Wheels (DOW) mobile radar observed this tornado as it crossed Mulhall. The DOW documented the largest ever observed core flow circulation with a distance of 1600 m between peak velocities on either side of the tornado, and a roughly 7 km (4 miles) width of peak wind gusts exceeding 43 m/s, making the Mulhall tornado the largest tornado ever measured quantitatively.

http://terrific-top10.com/tag/mulhall/

 

[Shawn Schuman]

That's what I've been wondering. Maybe someone (Jeff S?) could weigh in on how width is determined via mobile radar. I've always been curious.

 

[Jason Harris]

And if it's basically circulation of winds vs. damage path, do we know the circulation diameter of El Reno to compare with Hallam?

 

[rdale]

I think this puts everything in perspective and no longer feel there is anything anyone could have done to prevent this other than not chasing that day.

So you're saying there was no safe way to be in the vicinity of that storm? I think there are many many options - most of which involve putting more than a mile between you and the circulation.

 

[Kevin Franz]

So you're saying there was no safe way to be in the vicinity of that storm? I think there are many many options - most of which involve putting more than a mile between you and the circulation.

No, I'm not saying that at all. I agree and if I would have been out, I would have been to the south. That being said, this is where they gather their data, very close to the tornado. I feel this helps show that
it is likely the size/power of this beast was at fault for the injuries/deaths, not a lack of escape routes etc.

Death sucks and human nature is to find the cause or who was at fault. I think we now know the cause of everything. Just my .02

 

[MGalloway]

Seems reasonable for it to be predominately associated with HP storms which have access to ridiculous amounts of moisture close to the surface, and the storm enters some sort of strengthening phase as everything maxes out for a bit. I doubt that any storm could sustain a tornado of that size for any prolonged length of time as it requires an incredible amount of energy to generate (as in, more than a lot of atomic bombs are capable of).

Does anybody ever do any energy calculations in terms of wind field size and intensity? It'd be interesting to see what the correlation is and if there is a way of predicting when a storm such as this has the potential to change drastically in character.

A few years ago, I found a paper that discussed using fractal analysis with predicting hurricane intensity/damage. Although the main paper deals with health care, the first paragraph discussed looking at landfalling hurricanes, wind speeds, and patterns in the data (the original paper is here). I wonder if there is a way of figuring out if there is an overall size/strength/character "transition point" for tornadoes based on the size of the meso and/or number/size of suction vortices occurring.

 

[Robert Edmonds]

If you assume a 2.6 mile diameter 1km tall cone, with wind speeds on average 100mph inside of it, you're looking at ~10^13 Joules of kinetic energy (from .5*m*v^2). Choose your own values and check me, also depends on if you assume uniform, rankine (truncated at some radial distance), etc. The first atomic bomb was ~1/10th that in terms of energy released. Note this is not the amount of work applied to the surface for destruction.

 

[Caleb Chevalier]

Brief two cents: I'd be inclined to think that the width was calculated by the size of the damage path, not the circulation. If this is the case, the damage extent would likely be wider than the "tangible" tornado itself because of the extreme inflow and such. I'm sure it was a monster either way, though.