Enhanced Fujita Ratings Debate Thread

[Grand Poo Bah]

Here’s a more formal thread on the calculation of wind speeds near the surface in tornadoes from cycloidal markings/scattering in fields. Seems to certainly have some promise.

Evaluating the Viability of Surface Marks to Estimate Tornado Winds in Rural Areas

Tornadoes cause significant damage, injuries and fatalities worldwide. Tornado-based design for structures was introduced in ASCE 7-22, and design for tornado loading will continue to become more common in tornado prone regions and for certain structures in the United States. One parameter used...

ui.adsabs.harvard.edu

Wow! This is fascinating. It was Published almost two years ago. I wonder why the Washington, IL tornado still hasn't been upgraded.

An average of all the wind speeds for each individual loop was calculated to obtain the estimated wind speed for that section of the track. From the cycloidal surface marks, the Washington tornado had an average wind speed estimate from as low as 184 mph to as high as 219 mph across multiple areas of its path. The high wind area had individual surface mark wind speeds from 205 mph to 231 mph in addition to limitations with the accuracy of loop width and height measurements. Estimates of wind speed were then compared with wind speed estimates using the EF scale from nearby structures. The peak wind of 219 mph occurred immediately after Washington, IL and a residential neighborhood.

 

[SouthFLwx]

Also in Dawson Springs the tornado quite suddenly intensified as it crossed the eastern side of town producing relatively extreme damage,

View attachment 47224View attachment 47225

Higher end of vegetation damage, with some debarking and rootballing. This is probably a bit easier in a densely populated area though.

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There was a small industrial district right on the edge of town. Multiple larger buildings were destroyed here.

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Debris was once again granulated and wind rowed, and trees were mangled - as was common with this tornado throughout the track.

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The NWS used 2 EF4 DIs in the town, the highest being 180mph, however you can see on DAT they missed numerous structures.

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If you watch the aerial damage videos there are so many slabs where homes are almost completely covered in debris from other structures to the point they aren't visible. I don't find it impossible to think there may have been one home perhaps well built enough for an EF5 rating that was not surveyed, but there was also plenty of very subpar construction used. It's just one of those things where I think we will never know.

Also in my personal opinion, when tornadoes move through densely populated areas, especially quickly - the pure abundance of debris makes it harder to achieve the granulated, wind rowed, slab swept clean look so the tornado looks less intense (similar occurred in Rolling Fork and Greenfield). That's partly what makes tornadoes like Moore and Smithville (you could even argue Washington, IL) so extremely impressive when they completely swept clean almost all debris in the areas they impacted.

I think you make alot of great points here. Dawson Springs has some of the worst damage along the tornado’s track and is definitely close to EF5 intensity. The mass devastation and complete destruction of neighborhoods is definitely what leads me to believe that the damage is more consistent with a high end EF4 (190-200 mph). Also yeah, the survey here wasn’t the best and likely had to do with the fact that NWS Paducah had so much damage to survey along the tornado’s track. Also glad you brought up Washington 2013 because that one should have been an EF5.

 

[AJS]

Pretty wild stuff while it was traversing the distance between Cayce and MayfieldView attachment 47233View attachment 47234View attachment 47232

Jeez, i’ve never really seen the damage from the beginning of its path, that is some pretty gnarly tree damage.

 

[WeathermanLeprechaun]

It's not just Vilonia and Mayfield. There's a ton more. So much more. Listing just from structural damage alone:

Louisville the day after Vilonia
Pilger family later that year (at least 3 EF5 candidates)
Rochelle 2015
Holly Springs 2015 (New Wren reborn)
Chapman 2016 (rock solid EF5 DI)
Canton 2017 (maybe?)
Camp Crook 2018
Bassfield 2020 (Evidence seems to be piling up for an EF5 at the cabin)
Rolling Fork 2023 (Likely EF5 at Family Dollar)

Not even including likely contextual EF5s like Cisco, Monette or Matador.

So, yea

Those are the most POPULAR candidates of mine. Most of yours i agree with, and others i just don't know enough about their particular insights of damage to argue against (I know Camp Crook was pretty gnarly contextually, but i forget the real specifics)

Regarding Pilger, Rochelle and Holly Springs, I agree on the first two but Holly Springs I've always seen as a strong candidate, just nothing too concrete to justify my opinion
Some of the damage I've seen with Chapman on this forum certified it as so because even Topeka went ahead and said it would've been a EF5 had it stuck HEAD ON
Canton, eh, I'm not too sure on it. Probably mid end-high end EF4 based on contextuals, but was structural damage that pristine to say so?
Camp Crook like I've said was pretty vicious but it's one of those cases I'd have to look back over
Bassfield, with the new rules, this is increasing, so I'm leaning on yes here
Rolling Fork: i have no doubt this was a EF5 but the Family Dollar is so borderline, I'm not sure because some Jackson surveyor made a comment about it and it got misinterpreted a bit

 

[Ozonelayer]

To think all of this re-evaluation is due to NWS Grand Forks and the first EF-5 in 12 years.

Anyway, here are EF-5 candidates based on how confident I am that they should be rated EF-5 in no particular order.

High Confidence:

Mayfield
Vilonia
New Wren
Tuscaloosa
Chickasha
Goldsby
Ringgold
Chapman

Low-Medium Confidence:

Bassfield-Soso
Rolling Fork
Tri-State '21
Matador
Rochelle-Fairdale
Holly Springs

Honorable Mentions:
Diaz
Greenfield
Probably a few others Im forgetting.