Enhanced Fujita Ratings Debate Thread

[TH2002]

I mean construction is just as important as the debris pattern, if not more so. If that’s a subfloor, then we can automatically deduce that the walls separated from where they were nailed into the floor, rather than the entire house being ripped from the bolts along its basement foundation. That’s an important distinction that can mean a world of difference when it comes to EF rankings.

I totally hear you, if this a subfloor then an EF5 rating is precluded, and if there was debris on the foundation before the apparent cleanup, an EF5 rating is precluded. And even if it is in fact a concrete slab and it was swept away by the tornado, they'd find some bs excuse to keep the rating at EF4. Just so many questions I have about that house which will I guess remain unanswered cause there is no DI at that location.

 

[buckeye05]

I totally hear you, if this a subfloor then an EF5 rating is precluded, and if there was debris on the foundation before the apparent cleanup, an EF5 rating is precluded. And even if it is in fact a concrete slab and it was swept away by the tornado, they'd find some bs excuse to keep the rating at EF4. Just so many questions I have about that house which will I guess remain unanswered cause there is no DI at that location.

Yeah it speaks to a larger problem: half-*ssed surveys. I’m not sure what the excuse is, as NWS Norman had a damage point for every single house damaged by Moore 2013. Painstakingly detailed, like this one should have been.

 

[MNTornadoGuy]

The closest views of the Cambridge Shores slabs I could find so far.

 

[buckeye05]

The closest views of the Cambridge Shores slabs I could find so far.

I’m pretty sure you’re already aware, but if you’re looking for EF5 candidate houses, those aren’t the ones in question because they still have the subfloors attached. I’ll link some screencaps of the stronger candidates.

 

[buckeye05]

Ok. Here are the EF5 candidate homes in the Gilbertsville/Cambridge Shores area. Poured concrete foundations, and total removal of subflooring.

 

[MNTornadoGuy]

Aerial view of that house in Bremen that had part of its concrete foundation shattered. There wasn’t any rebar in the broken foundation though. The tornado peaked in this area on radar and the mangling of vehicles, ground scouring, tree debarking, extensive wind-rowing and debris granulation are solid evidence that the tornado likely reached EF5 intensity in the area. The main thing is likely preventing a higher rating in this area is the poor-construction with most houses having a CMU foundation or poor-anchoring.


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[MNTornadoGuy]

Ok. Here are the EF5 candidate homes in the Gilbertsville/Cambridge Shores area. Poured concrete foundations, and total removal of subflooring.
View attachment 11152View attachment 11153View attachment 11154View attachment 11156View attachment 11157

I’m not sure if the 1st or 3rd photo are ones as there are massive chunks of debris and it wasn’t blown very far away from the house. The other ones could be though if they are well-anchored.

 

[buckeye05]

Aerial view of that house in Bremen that had part of its concrete foundation shattered. There wasn’t any rebar in the broken foundation though. The tornado peaked in this area on radar and the mangling of vehicles, ground scouring, tree debarking, extensive wind-rowing and debris granulation are solid evidence that the tornado likely reached EF5 intensity in the area. The main thing is preventing a higher rating in this area is the poor-construction with most houses have a CMU foundation or poor-anchoring.
View attachment 11150
View attachment 11151
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The contextual damage says it all right here. This is why construction doesn't always tell the whole story, and why whatever overhaul/redesign of the EF scale happens, needs to include contextual damage. For example, maybe a list of established "non-structural tornado intensity indicators" that can be used in context with established DI's, and have a pre-set limit of how far upper or lower-bound you can go. For example, there could be a range of ground scouring from "level 1 to level 5", ranging from say "some damage to surface vegetation" to "all surface vegetation gone, trench dug". A level one would allow a surveyor to add, say just a few MPH past what the structural integrity alone indicates, while a level 5 would allow a surveyor to go with EF5, even if only CMU foundations are present nearby for example. Same thing could be done for say, wind-rowing or vehicle movement. Obviously a very rudimentary idea, but one that would give specific values to contextual damage, making it so that higher wind speeds can be ascertained at homes that have clearly failed at a level well below the actual intensity of the tornado. If something like that was implemented, we'd have an EF5 rating with this one.

 

[andyhb]

Aerial view of that house in Bremen that had part of its concrete foundation shattered. There wasn’t any rebar in the broken foundation though. The tornado peaked in this area on radar and the mangling of vehicles, ground scouring, tree debarking, extensive wind-rowing and debris granulation are solid evidence that the tornado likely reached EF5 intensity in the area. The main thing is preventing a higher rating in this area is the poor-construction with most houses have a CMU foundation or poor-anchoring.

As a devil's advocate here, aside from a few homes in this area that clearly had CMU construction, I don't see how we're supposed to infer anything about the construction of others without ground-level photos of the sites.

Should note: there are some other places that are highly suspect beyond Cambridge Shores/Bremen that haven't been looked at much, but that's all I'll say on that for now.

 

[MNTornadoGuy]

 

[buckeye05]

I’m not sure if the 1st or 3rd photo are ones as there are massive chunks of debris and it wasn’t blown very far away from the house. The other ones could be though if they are well-anchored.

Yeah debris pattern wise, I’ve seen a lot worse. But construction/anchoring wise, this is the best I can find along the path given the information available.

 

[buckeye05]

One of the EF4 DIs in Bremen is this house that was completely obliterated. Not much is left of either the CMU foundation or the house itself.

Was impressed initially. But I see bulldozer tread marks in the dirt. Lots of debris cleanup, especially in the second pic. There was a photo of a bulldozed foundation in Hackleburg that was misinterpreted in a similar way.

 

[MNTornadoGuy]

Was impressed initially. But I see bulldozer tread marks in the dirt. Lots of debris cleanup, especially in the second pic. There was a photo of a bulldozed foundation in Hackleburg that was misinterpreted in a similar way.

Oh well I'll delete the second part then.

 

[TH2002]

One thing I've been thinking about lately is how a violent tornado that touches down in the Soviet Union of all places (Ivanovo 1984) with all the Soviet censorship and such can still get an F5 rating but a tornado in the United States hasn't been able to achieve an EF5 rating for a record long streak despite numerous tornadoes clearly reaching and/or causing damage indicative of such intensity. Something, (likely multiple things) is contaminating the rating of tornadoes in the US, and it's a MAJOR problem.

 

[MNTornadoGuy]

One thing I've been thinking about lately is how a violent tornado that touches down in the Soviet Union of all places (Ivanovo 1984) with all the Soviet censorship and such can still get an F5 rating but a tornado in the United States hasn't been able to achieve an EF5 rating for a record long streak despite numerous tornadoes clearly reaching and/or causing damage indicative of such intensity. Something, (likely multiple things) is contaminating the rating of tornadoes in the US, and it's a MAJOR problem.

Ivanovo's F5 rating is now disputed. It is listed as an F4 in the ESWD database and all recent studies. Though yeah there are definitely problems with the EF-scale.

 

[TH2002]

Ivanovo's F5 rating is now disputed. It is listed as an F4 in the ESWD database and all recent studies. Though yeah there are definitely problems with the EF-scale.

It may have been an F4, but still pretty crazy to think that in a country where information was so strictly controlled and many disasters were swept under the rug by the Soviet press (such as the Kursha-2 fire) you would think the Soviet survey teams would have done everything they could to make the tornado look less severe than it was, but they still gave it an F5 rating.

 

[TH2002]

It may have been an F4, but still pretty crazy to think that in a country where information was so strictly controlled and many disasters were swept under the rug by the Soviet press (such as the Kursha-2 fire) you would think the Soviet survey teams would have done everything they could to make the tornado look less severe than it was, but they still gave it an F5 rating.

Pretty much how survey teams in the US now (ESPECIALLY starting wtih Vilonia) do pretty much everything they can to not give tornadoes an EF5 rating: abuse of the lower bound value, going BELOW lower bound, overlooking/skipping DI's entirely, ignoring contextual evidence altogether, etc.

I'm sure survey teams aren't the only thing to blame however, and the problem probably goes far deeper than any of us could imagine.

 

[A Guy]

It may have been an F4, but still pretty crazy to think that in a country where information was so strictly controlled and many disasters were swept under the rug by the Soviet press (such as the Kursha-2 fire) you would think the Soviet survey teams would have done everything they could to make the tornado look less severe than it was, but they still gave it an F5 rating.

They didn't. The original Russian sources give an F4 rating, which is fair enough considering the information on the damage we actually have.

 

[buckeye05]

I’m not sure if the 1st or 3rd photo are ones as there are massive chunks of debris and it wasn’t blown very far away from the house. The other ones could be though if they are well-anchored.

Actually, are we looking at the same 1st photo? Looks like the cleanest sweep out of all of them. I'm referring to the crawlspace foundation home in the center of the photo. There's no sizable debris within the immediate vicinity.

 

[TH2002]

They didn't. The original Russian sources give an F4 rating, which is fair enough considering the information on the damage we actually have.

I've never seen any of the original sources mention an F4 rating. I wouldn't be surprised if they did, but the Russian sources I've looked that said F5.

Is there anything you can link me to? Maybe a scan of an old newspaper or something?