Enhanced Fujita Ratings Debate Thread

[andyhb]

I believe poor anchoring is somewhat overridden when an strong framed house is tossed whole.

Poor anchoring often is the reason why such a thing happens.

 

[TH2002]

My thoughts on the '74 Super Outbreak and reanalyzing its F5 tornadoes using the EF scale:

I'm confident that any reasonable WFO would rate Brandenburg EF5 even today. Not only was the contextual damage extraordinarily intense, but one anchor bolted home was swept away with such violence that it sustained total collapse of a poured concrete basement wall. That is something you rarely see and puts it in the upper echelon of tornadoes imo:

Also, perhaps somewhat controversially, I believe that Brandenburg was the strongest tornado of the 1974 Super Outbreak instead of Guin. Not saying Guin wasn't an F5, because it absolutely was, but Brandenburg's feats of damage were basically unmatched during the outbreak.

The other '74 Super Outbreak tornado I know of that swept away anchor bolted homes is ironically rated F4, the Mannsville, KY tornado. F4 is fine considering the block foundations and lack of trees 100% stripped of bark (at least from available photos), but I'm honestly a bit surprised it didn't get rated F5 considering some of the other tornadoes from that outbreak which did get the rating. May have even had a shot at an EF5 rating in the early years of the EF scale considering Rainsville, tbh.

Depauw might stand a chance for an EF5 rating based on this one home that was swept away and had its debris extensively wind rowed away from the foundation, but idk if it was well constructed or not. Still, I strongly suspect it reached its true peak intensity in Daisy Hill, but since the tornado is so poorly documented I don't think think I've ever seen any damage photos from that part of the path:

Xenia wouldn't get rated EF5 today due to the fact that the homes it swept away were not well anchored. Still, the scouring and granulation was pretty impressive, and as such the Xenia tornado falls in a bit of an unusual place imo - F5 but not EF5.

As another user already pointed out, Guin produced very impressive contextual damage (a close second behind Brandenburg) but the tornado not encountering any structures well built enough for an EF5 rating is a very real possibility.

Tanner 1 was probably the third most violent of the outbreak, and some of the homes it swept away appeared to be potentially well-constructed, but again I can't verify without ground level photos.

Tanner 2 was actually more violent than a lot of people give it credit for, and I actually agree with its F5 rating (there, I said it). Definitely wouldn't pass EF5 muster though.

That leaves Sayler Park. @MNTornadoGuy posted a great collection of aerials from this tornado at one point, but go figure the photos got vaporized and are no longer available. It's a shame since some of them may have even showed some potentially well constructed homes, but we'll never know for sure. Based on available ground level photos, I don't think it would pass EF5 muster though.

 

[Grand Poo Bah]

Poor anchoring often is the reason why such a thing happens.

I've got a bunch of tornado wind studies I found in the significant tornado thread I still need to read through. I don't know what type of winds are required to lift a whole house "Wizard of Oz" style, but I hope to find the answers there. I can share what I have downloaded if anyone else would be interested in reading them! If I find anything concrete I'll share it in here, even if it contradicts my current beliefs.

 

[ColdFront]

My thoughts on the '74 Super Outbreak and reanalyzing its F5 tornadoes using the EF scale:

I'm confident that any reasonable WFO would rate Brandenburg EF5 even today. Not only was the contextual damage extraordinarily intense, but one anchor bolted home was swept away with such violence that it sustained total collapse of a poured concrete basement wall. That is something you rarely see and puts it in the upper echelon of tornadoes imo:

Kentucky’s only F5. Mayfield made an attempt.

I’ll have to re-check the records, but I think KY alone had 10 or 11 violent tornados that day.

There was one supercell that I’m almost sure originated southwest of Nashville that tracked northeast over 250+ miles to Mt Sterling Kentucky. It was responsible for 6 (probably more undetected) tornados, 2 F4s and 2 F3s. Its tornados 60-65 on Fujita’s map. It actually produced the Mannsville Storm @TH2002

Edit: technically, Sayler Park was in KY briefly and was a F5, but only did damage up to F2 while in KY.

 

[AJS]

Finally got a chance to take a better look at these pics on a bigger screen, and I gotta say I'm absolutely blown away This is the perfect example of houses that weren't just blown over. The lack of debris anywhere in sight tells me the houses were lifted whole and tossed long distances. Every contextual indicator you could possibly ask for is present too.

I see insane ground scouring and entirely stripped trees (on the ground) here:

View attachment 37265

Does anyone know where this pic was taken? It looks like it could be from one of the fields directly adjacent to this neighborhood.

View attachment 37268

I see possible evidence of trenching here:

View attachment 37266

That evidence is further supported from this alternate angle, where you can see the ripped up clumps of dirt on the driveway.

View attachment 37267

I'm not even sure where this house (circled) came from! I drew arrows next to contextuals that indicate wind direction as the tornado passed over and they aren't saying the debris is from the slab directly above:

View attachment 37270

Here's another angle... There are no other houses in sight. This indicates large chunks of this home were carried a half mile or more. The smaller circle up top could be our trenching. The tree lines in the distance of both photos appear to match, but no way to say for sure. I'll look in the DAT and see if I can find anything.

View attachment 37271

I've seen a lot of tornado damage photos over the last 20 years, and I gotta say, this is the most impressive damage I've ever seen in my life. I'm dumbfounded it wasn't rated EF5. From my seat, it looks like the homes that were anchored were severely granulated and wind-rowed, and the houses without anchors are literally just gone. No trace. They're in the Land of Oz.

Btw, while it is some of the most impressive damage i’ve personally seen, I do think some tornadoes have caused more impressive damage, but it’s no doubt the damage in Bremen pointed to winds well into the EF5 range.

 

[Tomcats Forever!]

Kentucky’s only F5. Mayfield made an attempt.

I’ll have to re-check the records, but I think KY alone had 10 or 11 violent tornados that day.

There was one supercell that I’m almost sure originated southwest of Nashville that tracked northeast over 250+ miles to Mt Sterling Kentucky. It was responsible for 6 (probably more undetected) tornados, 2 F4s and 2 F3s. Its tornados 60-65 on Fujita’s map. It actually produced the Mannsville Storm @TH2002

Edit: technically, Sayler Park was in KY briefly and was a F5, but only did damage up to F2 while in KY.

Is that the record for # of violent tornados in one state in a single day?

 

[ColdFront]

Is that the record for # of violent tornados in one state in a single day?

Good question. It was 9 tornados that did F4 damage documented in the state. 11 if you included overall ratings regardless of where the damage was documented (Sayler Park & a KY/TN state line storm).

One that immediately comes to mind was Palm Sunday 1965 and Indiana, but that was 8.

The obvious answer would be Alabama on 4/27/11 with 10 in a record that won’t be broken for a long time. I’ll have to check if the Enterprise MS tornado did any EF4 damage in Alabama. It’s 11 if you include overall rating regardless of where damage was documented.

 

[AJS]

My thoughts on the '74 Super Outbreak and reanalyzing its F5 tornadoes using the EF scale:

I'm confident that any reasonable WFO would rate Brandenburg EF5 even today. Not only was the contextual damage extraordinarily intense, but one anchor bolted home was swept away with such violence that it sustained total collapse of a poured concrete basement wall. That is something you rarely see and puts it in the upper echelon of tornadoes imo:

Also, perhaps somewhat controversially, I believe that Brandenburg was the strongest tornado of the 1974 Super Outbreak instead of Guin. Not saying Guin wasn't an F5, because it absolutely was, but Brandenburg's feats of damage were basically unmatched during the outbreak.

The other '74 Super Outbreak tornado I know of that swept away anchor bolted homes is ironically rated F4, the Mannsville, KY tornado. F4 is fine considering the block foundations and lack of trees 100% stripped of bark (at least from available photos), but I'm honestly a bit surprised it didn't get rated F5 considering some of the other tornadoes from that outbreak which did get the rating. May have even had a shot at an EF5 rating in the early years of the EF scale considering Rainsville, tbh.

Depauw might stand a chance for an EF5 rating based on this one home that was swept away and had its debris extensively wind rowed away from the foundation, but idk if it was well constructed or not. Still, I strongly suspect it reached its true peak intensity in Daisy Hill, but since the tornado is so poorly documented I don't think think I've ever seen any damage photos from that part of the path:

Xenia wouldn't get rated EF5 today due to the fact that the homes it swept away were not well anchored. Still, the scouring and granulation was pretty impressive, and as such the Xenia tornado falls in a bit of an unusual place imo - F5 but not EF5.

As another user already pointed out, Guin produced very impressive contextual damage (a close second behind Brandenburg) but the tornado not encountering any structures well built enough for an EF5 rating is a very real possibility.

Tanner 1 was probably the third most violent of the outbreak, and some of the homes it swept away appeared to be potentially well-constructed, but again I can't verify without ground level photos.

Tanner 2 was actually more violent than a lot of people give it credit for, and I actually agree with its F5 rating (there, I said it). Definitely wouldn't pass EF5 muster though.

That leaves Sayler Park. @MNTornadoGuy posted a great collection of aerials from this tornado at one point, but go figure the photos got vaporized and are no longer available. It's a shame since some of them may have even showed some potentially well constructed homes, but we'll never know for sure. Based on available ground level photos, I don't think it would pass EF5 muster though.

I think Brandenburg was the strongest tornado in Kentucky history. With Mayfield being an easy #2.

 

[buckeye05]

Btw, while it is some of the most impressive damage i’ve personally seen, I do think some tornadoes have caused more impressive damage, but it’s no doubt the damage in Bremen pointed to winds well into the EF5 range.

There’s no doubt that Mayfield contained EF5 winds. There are three areas where I feel it could have gotten an EF5 rating had things been slightly different:

1.) Cambridge Shores: Construction quality and DOD at multiple homes was enough for EF5, but contextual evidence fell short. Had there been some high-end scouring, debarking, vehicle damage, debris granulation, etc in that area, EF5 would have been appropriate.

2.) Bremen: Context was there, this area had “the look”. Literally ONE single anchor-bolted house with a poured concrete foundation is all it would have taken. Just one, and we would have had it. Came so, so close here.

3.) Mayfield: The least obvious of the three, but the near-total destruction the First Presbyterian Church in downtown Mayfield may have actually flirted with EF5 intensity. A few parts of the building were left standing, but it was mostly leveled and close-ups show very thick masonry walls with some reinforcement. If it had been totally flattened, EF5 likely would have been the right call. I’d honestly like to see a detailed engineering analysis of this specific building to make sure a 200+ MPH damage indicator wasn’t missed here.

 

[buckeye05]

I can say with newfound confidence, it would honestly depend on the office doing the survey. @buckeye05 has endorsed the Norman WFO, so I gotta agree it'd probably still be rated EF5 if the same damage happened it the same place today.

Yeah OUN is actually pretty liberal with their ratings, and despite the mess that was the 5/24/2011 surveys, they do know what EF5 damage looks like. I think we can chalk that day up to new hires (Kiel Ortega mainly) being overly cautious, because they’ve been great since then. Their breakdown of how to define EF5 house damage in Moore 2013 was spot-on. There were actually multiple homes where they went with EF5 despite minor construction flaws like missing toe-nails, because they concluded that the contextual damage was so violent that a few missing nails didn’t really matter. THAT is reasonable surveying, and it was a great case-study in defining EF5 damage without nit-picking. Unfortunately, Vilonia happened the following year, which I feel had a devastating impact on future surveys across the US by setting a terrible precedent, and casting doubt.

 

[ColdFront]

3.) Mayfield: The least obvious of the three, but the near-total destruction the First Presbyterian Church in downtown Mayfield may have actually flirted with EF5 intensity. A few parts of the building were left standing, but it was mostly leveled and close-ups show very thick masonry walls with some reinforcement. I’d honestly like to see a detailed engineering analysis of this specific building to make sure a 200+ MPH damage indicator wasn’t missed here.

That’s actually a great point on the church. Compared to Cambridge Shores, Bremen, and even at one time the UK Research Facility, the actual Mayfield portion doesn’t get mentioned a lot.

Is there precedent for WFOs to take into account additional detailed engineering analysis? I know in the official press release for the Rainsville EF5 they mentioned findings from a “forensic analysis”. Was always curious what that entailed and how many other WFOs have taken the time to do something similar.

 

[AJS]

There’s no doubt that Mayfield contained EF5 winds. There are three areas where I feel it could have gotten an EF5 rating had things been slightly different:

1.) Cambridge Shores: Construction quality and DOD at multiple homes was enough for EF5, but contextual evidence fell short. Had there been some high-end scouring, debarking, vehicle damage, debris granulation, etc in that area, EF5 would have been appropriate.

2.) Bremen: Context was there, this area had “the look”. Literally ONE single anchor-bolted house with a poured concrete foundation is all it would have taken. Just one, and we would have had it. Came so, so close here.

3.) Mayfield: The least obvious of the three, but the near-total destruction the First Presbyterian Church in downtown Mayfield may have actually flirted with EF5 intensity. A few parts of the building were left standing, but it was mostly leveled and close-ups show very thick masonry walls with some reinforcement. If it had been totally flattened, EF5 likely would have been the right call. I’d honestly like to see a detailed engineering analysis of this specific building to make sure a 200+ MPH damage indicator wasn’t missed here.

But CalebRoutt said there’s no require size for debris granulation and that Cambridge Shores had granulation.

Just joking around btw.


I feel like underrated areas of damage that don’t get brought up a lot as well are Dawson Springs and Cayce. The Cayce area had intense scouring and some pretty intense tree damage and the damage scope around Dawson Springs was just remarkable. Looked like Tuscaloosa and Joplin.

 

[buckeye05]

That’s actually a great point on the church. Compared to Cambridge Shores, Bremen, and even at one time the UK Research Facility, the actual Mayfield portion doesn’t get mentioned a lot.

Is there precedent for WFOs to take into account additional detailed engineering analysis? I know in the official press release for the Rainsville EF5 they mentioned findings from a “forensic analysis”. Was always curious what that entailed and how many other WFOs have taken the time to do something similar.

The only thing I can think of like that is Tim Marshall’s re-analysis of Greensburg High School a few years ago. He cited the thickness of the masonry walls and the total structural collapse to conclude that it was the most impressive damage to a school building he had seen, and likely EF5-worthy. There’s a presentation video out there somewhere where he discusses his updated findings/opinion on the rating of that building.

I feel like the church could use a similar post-analysis.

 

[AJS]

The only thing I can think of like that is Tim Marshall’s re-analysis of Greensburg High School a few years ago. He cited the thickness of the masonry walls and the total structural collapse to conclude that it was the most impressive damage to a school building he had seen, and likely EF5-worthy. There’s a presentation video out there somewhere where he discusses his updated findings/opinion on the rating of that building.

I feel like the church could use a similar post-analysis.

If I remember correctly, Tim thought the construction quality of the church to be very impressive. I can’t find the tweet, but I think it may be somewhere in the December 10, 2021 thread.

 

[AJS]

Also, I know this home was part CMU foundation and part concrete foundation, but this damage photo has always impressed the hell out of me. I mean, the tornado absolutely ravaged this home to shreds and even managed to tear apart the cinder blocks from the foundation in Smithville like fashion.
In addition, you can see the scoured ground plastered all around the home. I really feel like this home truly shows how intense the tornado was Bremen.

 

[eep]

My thoughts on the '74 Super Outbreak and reanalyzing its F5 tornadoes using the EF scale:

I'm confident that any reasonable WFO would rate Brandenburg EF5 even today. Not only was the contextual damage extraordinarily intense, but one anchor bolted home was swept away with such violence that it sustained total collapse of a poured concrete basement wall. That is something you rarely see and puts it in the upper echelon of tornadoes imo:

Also, perhaps somewhat controversially, I believe that Brandenburg was the strongest tornado of the 1974 Super Outbreak instead of Guin. Not saying Guin wasn't an F5, because it absolutely was, but Brandenburg's feats of damage were basically unmatched during the outbreak.

The other '74 Super Outbreak tornado I know of that swept away anchor bolted homes is ironically rated F4, the Mannsville, KY tornado. F4 is fine considering the block foundations and lack of trees 100% stripped of bark (at least from available photos), but I'm honestly a bit surprised it didn't get rated F5 considering some of the other tornadoes from that outbreak which did get the rating. May have even had a shot at an EF5 rating in the early years of the EF scale considering Rainsville, tbh.

Depauw might stand a chance for an EF5 rating based on this one home that was swept away and had its debris extensively wind rowed away from the foundation, but idk if it was well constructed or not. Still, I strongly suspect it reached its true peak intensity in Daisy Hill, but since the tornado is so poorly documented I don't think think I've ever seen any damage photos from that part of the path:

Xenia wouldn't get rated EF5 today due to the fact that the homes it swept away were not well anchored. Still, the scouring and granulation was pretty impressive, and as such the Xenia tornado falls in a bit of an unusual place imo - F5 but not EF5.

As another user already pointed out, Guin produced very impressive contextual damage (a close second behind Brandenburg) but the tornado not encountering any structures well built enough for an EF5 rating is a very real possibility.

Tanner 1 was probably the third most violent of the outbreak, and some of the homes it swept away appeared to be potentially well-constructed, but again I can't verify without ground level photos.

Tanner 2 was actually more violent than a lot of people give it credit for, and I actually agree with its F5 rating (there, I said it). Definitely wouldn't pass EF5 muster though.

That leaves Sayler Park. @MNTornadoGuy posted a great collection of aerials from this tornado at one point, but go figure the photos got vaporized and are no longer available. It's a shame since some of them may have even showed some potentially well constructed homes, but we'll never know for sure. Based on available ground level photos, I don't think it would pass EF5 muster though.

It's insanely frustrating how poorly documented the 1974 Super Outbreak is compared to other events even of its generation. Really makes it incredibly hard to compare it with 2011, which would be incredibly useful in helping classifying super outbreaks.

I'm particularly really curious to a lot of the F3s and F4s of the outbreak, as 2011 had few, albeit many of them during the main event were likely violent. Also F3s and F4s drop off the map significantly as time passes on, so I do wonder if that's just rating standards becoming more prominent and defined (especially in context of the outbreak sequence earlier this week), or if climatologically there was just more significance in older events (however I do lean towards the former).

 

[AJS]

A bit of a silly analogy, but in my opinion a good way to describe the damage seen in Bremen would be a lesser intense version of this damage seen in Smithville. I know Smithville is in another class of it’s own, but
the damage seen in Bremen was in my opinion contextually wise we’ve seen to ending the EF5 drought.

 

[Grand Poo Bah]

View attachment 37282
Also, I know this home was part CMU foundation and part concrete foundation, but this damage photo has always impressed the hell out of me. I mean, the tornado absolutely ravaged this home to shreds and even managed to tear apart the cinder blocks from the foundation in Smithville like fashion.
In addition, you can see the scoured ground plastered all around the home. I really feel like this home truly shows how intense the tornado was Bremen.

It's incredible looking damage. The amount of corn field debris peppered in is wild. DAT described it as "home gone".

 

[Grand Poo Bah]

Found the location of the trenching. Cayce, KY. So it was early in the tornado's path before it hit Mayfield. Has anyone here seen this video? It's incredible. The trenching was everywhere!

 

[TH2002]

Yeah OUN is actually pretty liberal with their ratings, and despite the mess that was the 5/24/2011 surveys, they do know what EF5 damage looks like. I think we can chalk that day up to new hires (Kiel Ortega mainly) being overly cautious, because they’ve been great since then. Their breakdown of how to define EF5 house damage in Moore 2013 was spot-on. There were actually multiple homes where they went with EF5 despite minor construction flaws like missing toe-nails, because they concluded that the contextual damage was so violent that a few missing nails didn’t really matter. THAT is reasonable surveying, and it was a great case-study in defining EF5 damage without nit-picking. Unfortunately, Vilonia happened the following year, which I feel had a devastating impact on future surveys across the US by setting a terrible precedent, and casting doubt.

I don't doubt that OUN is one of the WFO's that has the potential to end the EF5 drought, and that their survey of the Moore 2013 tornado is pretty much a perfect model of what exactly damage surveys should look like.

Still, 5/24/2011 isn't the only time they've screwed up...

Coincidentally, today is the 10th anniversary of one of those occasions - the 2015 Moore tornado they not only failed to issue a warning for, but gave a 115MPH EF2 rating. Even worse, they gave this DI a whopping 113MPH wind speed estimate. Come on... this is at least high-end EF2 damage, probably minimal EF3.

And enter the 2023 Cheyenne tornado, which produced impressive contextual damage - a mobile home was obliterated with its frame mangled and debris scattered long distances, trees were denuded with some spotty debarking and even some ground scouring occurred. What rating did they give it? High-end EF2.