Severe WX December 10 & 11, 2021 Severe Threat

[tornado examiner]

my personal rating (changes) for the december 10-11 2021 intense to violent tornadoes.

bowling green kentucky. EF4 (170mph)
saloma kentucky. EF4 (170mph)
tristate EF4. buff wind rating to (175 mph)
cayce to bremen kentucky Tornado. EF5 (200< mph) no definitive wind rating. like Joplin. just because we know it was certainly an EF5 in strength. with at least a little damage evidence to support it. not much but still...its enough if they weren't being so unnecessarily strict now-adays.

 

[OHWX97]

Interesting read.

 

[MNTornadoGuy]

A lot of people (weenies) disagree with the rating of the Mayfield EF4 but interestingly there are a smaller group of people that believe the Mayfield and Samburg tornadoes were the same tornado. They base this claim off of one or two small areas of weakly convergent and minor tree damage that they saw on aerial imagery between the two EF4s. I don’t really agree with their claim as there isn’t a continuous path of visible tornadic damage on aerial imagery. If it really was one tornado then it would have been at EF0/minimal EF1 intensity for 11 miles in that gap.

 

[TH2002]

A lot of people (weenies) disagree with the rating of the Mayfield EF4 but interestingly there are a smaller group of people that believe the Mayfield and Samburg tornadoes were the same tornado. They base this claim off of one or two small areas of weakly convergent and minor tree damage that they saw on aerial imagery between the two EF4s. I don’t really agree with their claim as there isn’t a continuous path of visible tornadic damage on aerial imagery. If it really was one tornado then it would have been at EF0/minimal EF1 intensity for 11 miles in that gap.

Isn't it at least fair to say Mayfield REACHED EF5 intensity? The EF4 rating can be debated till the cows come home, but I think given the incredible scouring that occurred near Cayce, it was capable of causing EF5 damage, but the strongest winds didn't impact any structures.

 

[buckeye05]

Yeah same pretty much. For me, Mayfield is a case of "I agree with the rating given what DIs were available, but I acknowledge that it was certainly capable of producing EF5 damage." It's not a case of "clear-cut EF5 damage occurred but was not properly identified and rated as such." like Vilonia, Chickasha, or Goldsby.

Though personally I'd say that it's intensity maxima was in the Bremen area, rather than Cayce.

 

[tornado examiner]

Isn't it at least fair to say Mayfield REACHED EF5 intensity? The EF4 rating can be debated till the cows come home, but I think given the incredible scouring that occurred near Cayce, it was capable of causing EF5 damage, but the strongest winds didn't impact any structures.

it pretty well did EF5 damage in princeton and bremen...of course massively butchered by the nws....

 

[TH2002]

it pretty well did EF5 damage in princeton and bremen...of course massively butchered by the nws....

Oh I have no doubt the tornado reached EF5 strength, in Bremen especially, and I do agree that parts of the survey were... iffy at best.

The Wikipedia article mentions that along Bethlehem Cemetery Ln "a row of four homes were obliterated, with debris scattered and wind-rowed long distances through fields across the street". I'm fully aware of the one home that had parts of its concrete flooring scoured, and the part-CMU part poured slab home that got its driveway scoured but I haven't seen photos of the others, at least not that I can recall off the top of my head. I will say the scouring was incredible, and the vehicle damage was certainly noteworthy.

Certainly some very violent damage in Princeton as well, including the research facility. Back to Wikipedia for a moment, "metal roof trusses [were] carried hundreds of yards from the structure and wrapped around trees". (edit: StormChasingVideo confirmed this, must have missed it. I apologize.) I also thought I remember hearing about a tractor trailer that was tossed hundreds of yards. A photo from Meadowbrook Dr

 

[TH2002]

On an unrelated note, I may be overlooking something obvious but was the "awesomely strong home" referred to in the one screenshot that home with the bizarre cinder block construction?

 

[buckeye05]

On an unrelated note, I may be overlooking something obvious but was the "awesomely strong home" referred to in the one screenshot that home with the bizarre cinder block construction?

Yes it was. Definitely odd construction.

it pretty well did EF5 damage in princeton and bremen...of course massively butchered by the nws....

The survey wasn’t thorough enough, but I wouldn’t say they butchered it. This was no Vilonia, at least in terms of damage intensity, as there was no clear-cut damage that explicitly met the EF5 criteria in those two towns you mentioned. I will say that in Bremen it was close and came down to construction, and had a traditional slab and bolts home been in the path in that area, I’d call it solid EF5, but there wasn’t anything like that in that area.

 

[tornado examiner]

On an unrelated note, I may be overlooking something obvious but was the "awesomely strong home" referred to in the one screenshot that home with the bizarre cinder block construction?

i think that one is the one with the large concrete slabs ripped off and shattered. the one not rated EF-5 because of..."mur contexual damage" where they ignore the rainsville... EF-5 of april 27 2011 where a similar thing occured. trees somewhat of a distance from the slabs home not having ef5 level damage after we've seen how small and precise violent vortices can be. sweeping away a home at EF-5 intensity while leaving the trees 30 yards away relatively untouched.

 

[UK_EF4]

i think that one is the one with the large concrete slabs ripped off and shattered. the one not rated EF-5 because of..."mur contexual damage" where they ignore the rainsville... EF-5 of april 27 2011 where a similar thing occured. trees somewhat of a distance from the slabs home not having ef5 level damage after we've seen how small and precise violent vortices can be. sweeping away a home at EF-5 intensity while leaving the trees 30 yards away relatively untouched.

One flaw with the EF scale which I think happens quite often is rating regarding contextual damage:
They often rate down based on contextual damage (Vilonia, parts of Bremen I think, others etc) however in instances of high end contextual damage they nowadays rarely if ever rate up. Not really anything groundbreaking here obviously but if the scale took in account for context I'm sure final ratings would probably reflect a tornado's true intensity more often than now.

 

[buckeye05]

i think that one is the one with the large concrete slabs ripped off and shattered. the one not rated EF-5 because of..."mur contexual damage" where they ignore the rainsville... EF-5 of april 27 2011 where a similar thing occured. trees somewhat of a distance from the slabs home not having ef5 level damage after we've seen how small and precise violent vortices can be. sweeping away a home at EF-5 intensity while leaving the trees 30 yards away relatively untouched.

Edit:

Bringing the heat down, but if you’re implying that construction and context shouldn’t have much bearing on ratings, you have a lot to learn.

Also, that house with the shattered concrete floor utilized strange construction methods, regardless of context. That wasn’t a strong EF5 candidate, despite what you are suggesting.

As I mentioned earlier, had that been a regular poured slab with anchor bolts, I wouldn’t be saying this.

 

[UK_EF4]

Okay... I have just seen this going around twitter, personally haven't had time to watch it (I have seen some say it raises more questions than answers), but I think it may be very relevant to some who disagreed with at least some aspects of 10/12 surveying (myself included). Can't wait to watch the whole thing when I get some spare minutes.

 

[andyhb]

Lol the Bremen 190 mph indicator is basically a carbon copy of the Vilonia stuff. Not rated EF5 because of standing trees nearby.

"But what kept us from EF5 is there were trees nearby which did not sustain major damage that you would expect."

 

[buckeye05]

OK first thing I noticed, they are saying it wasn't a true EF5 like Joplin which "struck more substantially built structures." While maybe not entirely wrong, construction quality was a big issue in Joplin, and the only confirmed EF5 structural damage was at the hospital (though I do believe a few office/medical buildings and some homes in the area also met the EF5 criteria). The Joplin tornado was NOT known for hitting a bunch of well-built structures, and many claim quite the opposite was the case. This leads me to believe that one of the biggest things that is causing the EF5 draught, is surveyors not knowing the specific details or having enough background info on past EF5 events, and what led surveyors to assign an EF5 rating. The comment about the construction in Joplin clearly shows misconception, and that the surveyors did NOT have an in-depth grasp on what happened in Joplin. To get a clear idea of what true EF5 damage looks like, one needs to look at past examples, and I have a feeling this isn't something that is done nearly enough by NWS employees. The outcome of this, I believe, is a vague and ambiguous concept of what EF5 damage actually is. I wonder what many surveyors would say when asked "What is the definition of EF5 damage? What do you need to see to assign an EF5 rating?". I would bet my savings that many wouldn't have a clear answer, many would give contradictory answers, and I bet many would give inaccurate answers that don't correlate with studies on the difference between EF4 and EF5 by people like LaDue, Marshall, and Ortega.

Bottom line, if there isn't a specific, crystal clear definition of EF5 damage in a surveyor's head already, it's not going to be assigned, because that surveyor won't even know what to look for. Events like Vilonia make the problem so much worse, because surveyors will see that damage and think "Well if that's not EF5, what is?" I bet multiple surveyors who once had confidence in what EF5 looks like, lost that confidence after Vilonia. Surveyors DESPERATELY need to deeply study recent EF5 events to see it isn't this unobtainable level of damage, and desperately need to get on the same page. This whole presentation reeked of "We're actually not that confident or knowledgeable about the difference between EF4 and EF5, but based on what others told us and what vague info we do have, this is our reasoning."

 

[buckeye05]

Lol the Bremen 190 mph indicator is basically a carbon copy of the Vilonia stuff. Not rated EF5 because of standing trees nearby.

"But what kept us from EF5 is there were trees nearby which did not sustain major damage that you would expect."

Which is totally weird for multiple reasons, the first one being that the odd foundation type wasn't the basis for keeping it at EF4 (that would have been my reasoning), and was based on some bs contextual discrepancy instead. The most ridiculous thing about that excuse is that it is in direct contradiction to an extensive 2013 AMS study that compared tree damage in Moore to structural damage nearby. What they found is that trees next to EF5 structures usually didn't snap or uproot, but were simply stripped clean of all limbs and bark. Standing trees are NOT a basis for a downgrade. Part of me wonders if they read the Vilonia survey and it came as a result of that.

 

[UK_EF4]

Lol the Bremen 190 mph indicator is basically a carbon copy of the Vilonia stuff. Not rated EF5 because of standing trees nearby.

"But what kept us from EF5 is there were trees nearby which did not sustain major damage that you would expect."

Yes... Just watched that part and came on here to comment.
1. What on earth was that polling thing? Some people were seriously suggesting a cracked foundation of a well built home should be rated EF2. To me, that is pretty ridiculous. I didn't quite understand what that was though, so if I am misunderstanding, please correct me.
2. The trees. This part really frustrated me. The trees were not right next to the structure (if I remember correctly). This sounds awfully 'I know more than NWS' and I apologise, but surely they must know that the strongest wind core can be narrow. and stuff like that, with the strongest winds being in one place and not a little distance away?

OK first thing I noticed, they are saying it wasn't a true EF5 like Joplin which "struck more substantially built structures." While maybe not entirely wrong, construction quality was a big issue in Joplin, and the only confirmed EF5 structural damage was at the hospital (though I do believe a few office/medical buildings and some homes in the area also met the EF5 criteria). The Joplin tornado was NOT known for hitting a bunch of well-built structures, and many claim quite the opposite was the case. This leads me to believe that one of the biggest things that is causing the EF5 draught, is surveyors not knowing the specific details or having enough background info on past EF5 events, and what led surveyors to assign an EF5 rating. The comment about the construction in Joplin clearly shows misconception, and that the surveyors did NOT have an in-depth grasp on what happened in Joplin. The best way to get an idea of what true EF5 damage looks like, one needs to look at past examples, and I have a feeling this isn't something that is done nearly enough by NWS employees. The outcome of this, I believe, is a vague and ambiguous concept of what EF5 damage actually is. I wonder how many surveyors when asked "What is the definition of EF5 damage? What do you need to see to assign an EF5 rating?". I would bet my savings that many wouldn't have a clear answer, many would give contradictory answers, and I bet many would give inaccurate answers that don't correlate with studies on the difference between EF4 and EF5 by people like LaDue, Marshall, and Ortega.

Bottom line, if there isn't a specific, crystal clear definition of EF5 damage in a surveyor's head already, it's not going to be assigned, because that surveyor won't even know what to look for. Events like Vilonia make the problem so much worse, because surveyors will see that damage and think "Well if that's not EF5, what is?" I bet multiple surveyors who once had confidence in what EF5 looks like, lost that confidence after Vilonia. Surveyors DESPERATELY need to deeply study recent EF5 events to see it isn't this unobtainable level of damage, and desperately need to get on the same page. This whole presentation reeked of "We're actually not the confident or knowledgeable about the difference between EF4 and EF5, but based on what others told us and what vague info we do have, this is our reasoning."

This as well. I noticed at the beginning they said 'surveying has changed in the past 10 years, we are learning more etc'. However, I must agree that change seems to be some idea of normal or generally well-built houses not being rated EF5, which occurred I would think after Vilonia (at least aided by it). They showed a comparison to a home in Cambridge Shores with some debris on the foundation, and a home in what I think was the Moore 2013 tornado, saying this is what EF5 damaged looks like etc, when some of the homes in Bremen looked like that, and were generally well built. shown on the same presentation.

Sorry for this jumbled rant. I hope that at least some of my points managed to come across, but this will be staying in my head for a while...

I wonder maybe, with vehicle + other DIs being added, we may see some change, I'm not sure though.

 

[buckeye05]

Also, did anyone notice that large orange text at the bottom of the page during the EF4 vs EF5 slide? It says "This tornado and its damage will be researched for years to come. Evidence may arise that could push it into the EF5 category."

So they are EXPLICITLY saying that after all this, they are STILL considering an upgrade? Personally, this one can go either way rating wise imo, as I think this one did reach EF5 intensity based on contextual clues, but there wasn't any "slam dunk" EF5 structural damage from what I have seen. But it's at least a silver lining knowing that upgrades well after the fact are indeed an option.

 

[Shakespeare 2016]

Which is totally weird for multiple reasons, the first one being that the odd foundation type wasn't the basis for keeping it at EF4 (that would have been my reasoning), and was based on some bs contextual discrepancy instead. The most ridiculous thing about that excuse is that it is in direct contradiction to an extensive 2013 AMS study that compared tree damage in Moore to structural damage nearby. What they found is that trees next to EF5 structures usually didn't snap or uproot, but were simply stripped clean of all limbs and bark. Standing trees are NOT a basis for a downgrade. Part of me wonders if they read the Vilonia survey and it came as a result of that.

There was some really incredible tree debarking in Greensburg but houses that were rated EF5 in Greensburg didn't usually have much contextual damage next to them.

 

[buckeye05]

Ok so mystery solved with the UK Research Facility. The CMUs that connected the walls to the foundation lacked rebar, and were weakly anchored by small clips. That's a big structural flaw. While the blueprints that were uncovered show a very impressive construction plan, it doesn't appear to have been fully followed by the construction crew.