Most Impressive or Strongest Tornado of the Last 20 Years?

[Jeff Snyder]

Originally posted by Glen Romine
Certainly the F-5 damage in Moore wasn't nearly as impressive - can't recall seeing anything at Jarrell level at Bridge Creek either, but do recall the damage there looking more impressive than in Moore.
Glen

True, but who's to say Bridge Creek wouldn't have looked like Jarrell had the Bridge Creek tornado moved much slower like the Jarrell tornado? I guess forward motion is inherent in an F-scale rating, both because structure damage is proportional to ground-relative winds and because damage seems to be affected by tornado residence time (these two factors opposing each other). Regardless, is the Jarrell tornado more impressive because it moved slower (and thus had higher residence time over any particular place), or was it objectively stronger?

 

[Chris Lott]

I think that is what is most impressive about the Jarrell tornado-damage. It literally blew away everything, but one thing you have to remember if you have never been to Jarrell, there wasn't that much to blow away to start with. The damage that the Moore tornado did going through a big Metropolitan area, that was pretty impressive. Had the Moore tornado gone through Jarrell, it would have blown it off the map. Here are a couple of damage pics from Jarrell, still very impressive.
http://home.mchsi.com/~tomph/trip/jpeg/jarrell1.jpg

http://home.mchsi.com/~tomph/trip/jpeg/jarrell2.jpg

 

[Shane Adams]

I agree the Jarrell event was the most impressive damage I've ever seen, and I would've picked Jarrell....except that several experts have always downplayed its intensity, oweing to a nearly-stationary, slow track that ground everything down as it lumbered along. A lot of respected names believe it was only F3 and just sat over the same places for long durations.

I can see the argument from both sides, but if the F3 theory is true, this makes it less powerful IMO, as far as brute wind force. If it truly was an F5 because the winds were that destructive (not just airborne debris), than it gets my #1 vote.

 

[Glen Romine]

I understand the slow motion aspect in the tornado damage, as in how it would have aided in pulverizing everything in it's path, but it doesn't explain how it was all carried away (centrifuged?) from the subdivision. The materials of 40 homes, attendant vehicles, asphalt, trees excepting 2-3 foot stumps, all completely evacuated from the area. That's tough to attribute to weaker winds, no matter how long they stayed there. Remnants of cars were moved up to 1/2 mile I think I recall seeing, and cattle (not known for their aerodynamics) were moved up to 1/4 of a mile.

 

[Brian Stertz]

I guess we're into the classic battle of F5 intensity questioning....I guess the best way to handle this topic is to consider that each of these nasty tornadoes were not born of/thrived in the exact same conditions as each other. I would have to agree that Jarrell's F5 was horrific in that it not only flattened stuff and swept it clean, it also turned things into very small fragments of debris. I would also have to say that I had a nice clear view of a swath of scoured earth/vegetation of the May 3rd tornado right after it had passed by. This was by far the most stunning and severe tornado damage I have ever seen personally. I did manage to see the Andover damage path a month after it had it happened. I would have to say that still the May 3rd damage swath was still more intense. There are a ton of factors at work when these atmospheric brush hogs cut loose, and it is hard to pin exacts when so many factors may have not been exactly known, or at least added into the equation and "totaled".

 

[Bill Tabor]

Originally posted by Chris Lott
I think that is what is most impressive about the Jarrell tornado-damage. It literally blew away everything, but one thing you have to remember if you have never been to Jarrell, there wasn't that much to blow away to start with. The damage that the Moore tornado did going through a big Metropolitan area, that was pretty impressive. Had the Moore tornado gone through Jarrell, it would have blown it off the map. Here are a couple of damage pics from Jarrell, still very impressive.
http://home.mchsi.com/~tomph/trip/jpeg/jarrell1.jpg

http://home.mchsi.com/~tomph/trip/jpeg/jarrell2.jpg

I heard they were brick at Jarrell or at least partial brick which is similar to what was at Moore just east of I35 - both of which I toured. I believe I remember seeing some on the outskirts of the path at Jarrell still standing too. I took a bunch of pics back then but forgot where I put them. I should try and find them and post them to the net.

As for Jarrell moving slower - that does give it more time over target to grind; however a faster moving tornado can also do more damage because of it's right front quadrant (assuming cyclonic) - forward momentum being added to the tornado. This could be between 0 to 70mph typically. That can make a big difference too, but I'd say sitting over something longer has more effect. Still you have to keep in mind that since F-scale is damage based only - it doesn't take into account the actual tornado speed of movement across the ground - that is implicit in the damage results - as I believe Jeff mentioned. So to speculate on which one possibly had higher wind speeds and so would be considered more definitive I think is errant thinking as we really don't know. The tornado west of Moore where it received an F5 rating may have been measured at 318mph but that was some 50 meters or so above ground - we do not know surface wind speeds. Also we have no measurements of Jarrell or Andover for that matter of winds speeds to compare it to. We just have F-scale.

Oh PS Chris: Consider if the Jarrell tornado had gone through Moore! Imagine Moore with nothing left on the ground. Consider all the extra debris because it was a larger urban area. That grinder would have ground it even worse IMO! In this case 'slow speed kills', and perhaps a qualification of a truly devasting tornado is that not only does it have high wind speeds but it stays over the damage area longer.

I think everyone may be basing this on what they 'think' may have had the highest wind speed without really knowing for sure, not the fact that our sly little Jarrell tornado was a slow moving grinder of destruction and death.

 

[Bill Tabor]

Originally posted by samuel stone
I believe we are in the longest f-5 drought since at aleast the 50's (maybe longer) so we are definantly due for one. I think that is partially due to the fact that some houses these days are made to be able to withstand stronger winds wich would result in less dammage done to them hence a lower F-rating. Just a thought.

I doubt it is an F5 drought. I think it is more likely that a tornado capable of inflicting F5 damage hasn't hit a quality engineered structure so that a damage assessment of F5 could be made. Here are some thoughts from Chuck Doswell taken from some of his online writings:

"What we do know about tornado climatology says that there will be something on the order of 5-20 violent tornadoes (F4-F5) in any given year ... we certainly do not have a clear idea of where or when they will occur. It's noteworthy that tornado fatalities in a given year are not very closely related to the number of tornadoes in that year (or even to the number of F2 and greater tornadoes). Fatalities are most closely associated with bad luck, where strong or violent tornadoes strike in populated areas. "

From that I take it he means 5 to 20 F4 to F5 type tornadoes occur every year but only the occasional ones are detected by a case of 'bad luck' for those that get hit. For us chasers out there that means that one of the F0 rated torns you intercepted last season may truly have been an F5 at times it just never got a rating.

On the other hand in the sense of a drought as you mention it the odds maybe piling up against us and we may be due for a few detected F5 strikes to populated areas rather than just in the rural countryside.

 

[Dean L. Cosgrove]

"other" tornado vote - June 15, 1990 - Hitchcock

The following photos are of incredible tornado damage from a tornado June 15, 1990 in Hitchcock County, NE. In my opinion this tornado was a very strong F5 not an F4 as it was rated. I base this on the following damage shots that I took . I have been unable to find pics from --ANY-- tornado that equal the damage shown below .

I have observed damage from "officially" F5 rated tornadoes. These F5 tornadoes did throw vehicles for long distances and tear them into several pieces.

The June 15, 1990 tornado went beyond that. It tore vehicles including very heavy farm equipment into small and in some cases almost unrecognizable pieces.

The first pic shows debris that I collected from the path of this tornado. Shown here are pieces of cars, farm equipment , a piece of a fence post twisted severely on both ends and a cast iron skillet. The small green piece of metal is from a vehicle that I documented finding pieces of over a 2 mile path through hilly terrain. I was unable to locate any piece of that vehicle larger than about 2 feet long.

I have photos of this tornado taken by someone living in the area. I spoke to an insurance agent who said he measured the tornado path of up to 2 miles wide. Since I did not take the tornado pics I can not post them.

I do however have copies from the NWS publication "Storm Data" that show some of the pics I have in black and white. I will post the "Storm Data" pages if I receive permission from NWS to do so. Perhaps someone at NWS can confirm if it is ok for me to post 2 pages from "Storm Data"

The following comment is from "Storm Data" : " The owners also had a van for which they needed to find an identifiable part for insurance purposes; they found its fire wall 7 miles to the east."

Dean Cosgrove
http://windsweptchasetours.com/index.html

 

[Bill Tabor]

Here's a link to some Jarrell damage. I took a lot of pictures that looked quite a bit worse than these in my opinion. Most everything I found that I took pictures of was very small and shredded.

http://www.k5kj.net/jarrell.htm

 

[Pat Lawrence]

Originally posted by Shane Adams
I agree the Jarrell event was the most impressive damage I've ever seen, and I would've picked Jarrell....except that several experts have always downplayed its intensity, oweing to a nearly-stationary, slow track that ground everything down as it lumbered along. A lot of respected names believe it was only F3 and just sat over the same places for long durations.

I can see the argument from both sides, but if the F3 theory is true, this makes it less powerful IMO, as far as brute wind force. If it truly was an F5 because the winds were that destructive (not just airborne debris), than it gets my #1 vote.

Shane,

I was wondering who thought it only deserved an F3 rating, if you can recall. It would be interesting to learn what they based that value on.

Thanks

Pat

 

[Shane Adams]

I'm pretty sure Tim Marshall is one, but I can't be for certain. I just know I've been in conversations when Jarrell was brought up, only to have others downplay the tornado intensity due to little or no movement, and the "grinding down" of the same structures for several seconds.

 

[Chris Lott]

Excellent case study of May 27th and the Jarrell tornado.


http://www.vvm.com/%7Ecurtis/Jarrell/Jarrell.htm

Lon Curtis and Al Moller lay it all out in this study.

 

[Pat Lawrence]

Originally posted by Shane Adams
I'm pretty sure Tim Marshall is one, but I can't be for certain. I just know I've been in conversations when Jarrell was brought up, only to have others downplay the tornado intensity due to little or no movement, and the "grinding down" of the same structures for several seconds.

Thanks, Shane.

I was mainly interested in what caused them to arrive at this conclusion...could it be tornado loitering? Would be interesting if this is so as the Jarrell tornado performed some amazing, albeit destructive, feats!

Guess most can thank their "lucky stars" most tornadoes move right along, regardless of strength

Pat

 

[Bill Tabor]

Wanted to mention I just watched 'Tornado Intercept' or some name to that affect on National Geographic channel. After the alleged June 12th intercept for the first time Wurman was able to calculate winds from the DOW versus surface wind speed of the TIV vehicle. The result was the surface vehicle experienced 109 mph winds or 80% of the speed measured by the DOW 50 feet above ground.

I find this interesting and if this can be extrapolated and compared to Moore which was similarly measured with DOW of 318 mph that would make surface wind speed ~254 mph.

Thoughts?

 

[Andy Wehrle]

Originally posted by Bill Tabor

Still you have to keep in mind that since F-scale is damage based only - it doesn't take into account the actual tornado speed of movement across the ground - that is implicit in the damage results - as I believe Jeff mentioned.

Good point, Bill. Even though the F-scale is "supposed" to be only a damage scale, sometimes other factors are taken into account in the results. The Stoughton tornado, like the Jarrel event, was a slow-mover that remained over the same area for a considerable duration, and I believe this was considered as one of the deciding factors to rate it F3 instead of F4.