Severe WX December 10 & 11, 2021 Severe Threat

[Sawmaster]

The Vortmax

vortmaxblog.wordpress.com

Good article about Mayfield. One thing I notices in It was some pics near Flat Creek Road that I havn't seen before.

Many thanks for the link to this I was quite impressed learning how one unbroken damage path can be the 'transition' from one vortex to another in the same main circulation and how that occurs. But again we see the broken system of surveying I constantly complain about occurring here:
"Extensive ground scouring also occurred, in addition to producing a trench and perhaps pulling up chunks of pavement as it crossed US51. The trench that was produced was up to a foot deep according to meteorologist/storm chaser Simon Brewer. Nearby, large chunks of asphalt were also scoured up as the tornado crossed US51. The magnitude of damage in the mentioned area has really only been documented in 1 other tornado which was the 2011 Philadelphia MS EF5. However, there were no structures immediately adjacent to the vegetation damage and is also not a standard DI, thus EF5 couldn’t be given here despite winds likely exceeding 200 mph. On radar, the tornado was lofting debris up to 20,000 feet"

And again "The damage in Mayfield was catastrophic. Well built homes were wiped to their foundations, large masonry buildings were leveled, and other large metal buildings such as the Candle Factory were completely obliterated. Extreme vehicle damage also occurred, with some tossed upwards of 200-500 yards. Perhaps one of the most impressive vehicular damage feats occurred near the candle factory. Here, an SUV and a 9 ton farming combine were thrown a considerable distance away (at least 125 yards), and were literally fused together. Extensive ground scouring and wind rowing also occurred in this area, in addition so trees shredded up and debarked. Debris from the candle factory and other industrial buildings in that area were strewn up to around 0.75 miles away, some of which were blended within a swath of intense tree damage. The damage around the candle factory is comparable to the damage seen at the Hackleburg jean plant after the 2011 EF5 struck the town."
Why the obvious must be ignored when the truth is so patently clear is beyond me; how can any sane person justify this kind of logic? The NWS isn't seeking the truth, only criteria on a checklist, so the truth cannot become known. And if the truth isn't knowable then that renders whatever data is otherwise found as useless for comparison with other events so why even bother doing a survey?

Anyway back to the link. The water tower damage is amazing. Moriaty's calculation does contain some errata (and thanks to him for using the word "approximate" as well as noting some of this) in that water weighs slightly more, but more importantly his use of a sphere's Cd (drag coefficient) which would be considerably higher than for the oblate spheroid shape the water tower had. I'd love for someone who had the dimensions of the 'tank' portions (and using more precise numbers for everything) to run the numbers again which I think would show a considerably higher windspeed needed to do this damage. I also wonder if the phenomena of "vortex shedding" which occurs with cylindrical objects in a wind plays a role in water tower damage; if so the shedding frequency in winds like this would very high indeed, almost like a vibration versus a swaying motion, with such vibrations possibly affecting the integrity of mechanical connections.

Also of Cambridge Shores: "in this case the radar at KPAH (before losing power) was doing a fairly accurate job at sampling wind speeds associated with the tornado. The 170-190 mph wind speeds correlated very well with the damage seen at Cambridge Shores. Numerous homes (some well built in this area) were completely swept, trees were debarked, and extensive wind rowing and evidence of ground scouring also occurred."and the mention of the 'slabbed' house on Sherwood Drive pretty much confirms my postulation that this area was under-rated. Too the Princeton Country Club area damage, as well as that at the U of K research building again show an under-rating of obvious intensity. Also at Dawson Springs and Bremen.

A most comprehensive article which I will revisit when I have time to more deeply digest it. And I wish the upper management of the national NWS were bashed over the head with this article until they began to understand that allowing only exact parameters in rating tornadoes can give very erroneous results.

Phil

 

[MNTornadoGuy]

Many thanks for the link to this I was quite impressed learning how one unbroken damage path can be the 'transition' from one vortex to another in the same main circulation and how that occurs. But again we see the broken system of surveying I constantly complain about occurring here:
"Extensive ground scouring also occurred, in addition to producing a trench and perhaps pulling up chunks of pavement as it crossed US51. The trench that was produced was up to a foot deep according to meteorologist/storm chaser Simon Brewer. Nearby, large chunks of asphalt were also scoured up as the tornado crossed US51. The magnitude of damage in the mentioned area has really only been documented in 1 other tornado which was the 2011 Philadelphia MS EF5. However, there were no structures immediately adjacent to the vegetation damage and is also not a standard DI, thus EF5 couldn’t be given here despite winds likely exceeding 200 mph. On radar, the tornado was lofting debris up to 20,000 feet"

And again "The damage in Mayfield was catastrophic. Well built homes were wiped to their foundations, large masonry buildings were leveled, and other large metal buildings such as the Candle Factory were completely obliterated. Extreme vehicle damage also occurred, with some tossed upwards of 200-500 yards. Perhaps one of the most impressive vehicular damage feats occurred near the candle factory. Here, an SUV and a 9 ton farming combine were thrown a considerable distance away (at least 125 yards), and were literally fused together. Extensive ground scouring and wind rowing also occurred in this area, in addition so trees shredded up and debarked. Debris from the candle factory and other industrial buildings in that area were strewn up to around 0.75 miles away, some of which were blended within a swath of intense tree damage. The damage around the candle factory is comparable to the damage seen at the Hackleburg jean plant after the 2011 EF5 struck the town."
Why the obvious must be ignored when the truth is so patently clear is beyond me; how can any sane person justify this kind of logic? The NWS isn't seeking the truth, only criteria on a checklist, so the truth cannot become known. And if the truth isn't knowable then that renders whatever data is otherwise found as useless for comparison with other events so why even bother doing a survey?

Anyway back to the link. The water tower damage is amazing. Moriaty's calculation does contain some errata (and thanks to him for using the word "approximate" as well as noting some of this) in that water weighs slightly more, but more importantly his use of a sphere's Cd (drag coefficient) which would be considerably higher than for the oblate spheroid shape the water tower had. I'd love for someone who had the dimensions of the 'tank' portions (and using more precise numbers for everything) to run the numbers again which I think would show a considerably higher windspeed needed to do this damage. I also wonder if the phenomena of "vortex shedding" which occurs with cylindrical objects in a wind plays a role in water tower damage; if so the shedding frequency in winds like this would very high indeed, almost like a vibration versus a swaying motion, with such vibrations possibly affecting the integrity of mechanical connections.

Also of Cambridge Shores: "in this case the radar at KPAH (before losing power) was doing a fairly accurate job at sampling wind speeds associated with the tornado. The 170-190 mph wind speeds correlated very well with the damage seen at Cambridge Shores. Numerous homes (some well built in this area) were completely swept, trees were debarked, and extensive wind rowing and evidence of ground scouring also occurred."and the mention of the 'slabbed' house on Sherwood Drive pretty much confirms my postulation that this area was under-rated. Too the Princeton Country Club area damage, as well as that at the U of K research building again show an under-rating of obvious intensity. Also at Dawson Springs and Bremen.

A most comprehensive article which I will revisit when I have time to more deeply digest it. And I wish the upper management of the national NWS were bashed over the head with this article until they began to understand that allowing only exact parameters in rating tornadoes can give very erroneous results.

Phil

While most of it is fine he does have a few errors and things I disagree with. For example the source he cites when he sats that the tree damage was “worse than Hackleburg” actually says it was comparable to tornadoes like Tuscaloosa and did not refer to Hackleburg (STEER did not survey that tornado.) I have yet to see any near-total debarking of forests and shrubbery from Mayfield like what was produced by Hackleburg. Also I’m not convinced that it was one tornado as when I checked it myself on aerial imagery, the damage in the gap was pretty spaced out and spotty.

 

[pohnpei]

While most of it is fine he does have a few errors and things I disagree with. For example the source he cites when he sats that the tree damage was “worse than Hackleburg” actually says it was comparable to tornadoes like Tuscaloosa and did not refer to Hackleburg (STEER did not survey that tornado.) I have yet to see any near-total debarking of forests and shrubbery from Mayfield like what was produced by Hackleburg. Also I’m not convinced that it was one tornado as when I checked it myself on aerial imagery, the damage in the gap was pretty spaced out and spotty.

I also think there is no real soild evidence to back up the one tornado theory. It's more like a wishful thinking. Regardless to say, 165 miles was insane enough and we probably won't see another tornado tracked that long in our life.

 

[CalebRoutt]

While most of it is fine he does have a few errors and things I disagree with. For example the source he cites when he sats that the tree damage was “worse than Hackleburg” actually says it was comparable to tornadoes like Tuscaloosa and did not refer to Hackleburg (STEER did not survey that tornado.) I have yet to see any near-total debarking of forests and shrubbery from Mayfield like what was produced by Hackleburg. Also I’m not convinced that it was one tornado as when I checked it myself on aerial imagery, the damage in the gap was pretty spaced out and spotty.

If I said the tree damage was “worse” than Hackleburg I was probably mistaken. “Comparable to” would probably be better. This tornado was definitely comparable not only in terms of impact but the tree damage in a lot of areas look almost exactly the same. Also keep in mind tree damage in the winter vs spring/summer months may look different in terms of debarking. Check out the 2 photos below, the 1st from Hackleburg the other is from Cambridge Shores.

In terms of 1 track, a lot of the reason why it doesn’t “seem” like 1 track is because a lot of the path was over rural farmland. It’s much more difficult to see damage from a weak tornado if there’s no structures or trees. What very likely could have happened was the original tornado was beginning to occlude until a new circulation developed merged with the former circulation which lead to an intensification of the tornado. A similar thing occurred several times with the 2012 Henryville tornado.

 

[CalebRoutt]

With that said im glad everyone likes the article!

 

[MNTornadoGuy]

If I said the tree damage was “worse” than Hackleburg I was probably mistaken. “Comparable to” would probably be better. This tornado was definitely comparable not only in terms of impact but the tree damage in a lot of areas look almost exactly the same. Also keep in mind tree damage in the winter vs spring/summer months may look different in terms of debarking. Check out the 2 photos below, the 1st from Hackleburg the other is from Cambridge Shores.

In terms of 1 track, a lot of the reason why it doesn’t “seem” like 1 track is because a lot of the path was over rural farmland. It’s much more difficult to see damage from a weak tornado if there’s no structures or trees. What very likely could have happened was the original tornado was beginning to occlude until a new circulation developed merged with the former circulation which lead to an intensification of the tornado. A similar thing occurred several times with the 2012 Henryville tornado.

Seasons don’t affect the intensity of debarking, they only affect the tree resistance to being uprooted or snapped. The 1st EF4 produced extreme debarking to that one grove of trees but Mayfield did nothing that was comparable. Also there was plenty of forested areas that the circulation would have passed over in that gap and yet there was no tree damage over almost the entire area.

 

[CalebRoutt]

The debarking in Monette was impressive, but the tornado also didn’t dig a trench over a foot deep in that area. Seasons do effect the ability for debarking, as well as tree species. The tree damage at Bremen was just as bad as Hackleburg, and Monette. Note the trees at the bottom of this ravine. (Hackleburg 1st pic, Bremen in 2nd). Also keep in mind, Hackleburg caused tree damage to predominantly softwood trees as softwoods are the predominant species in AL as where hardwoods are the predominant species in Kentucky. I’ll also add that the tree damage in Tuscaloosa, and Joplin (which you say they were compared to) where just as bad as Hackleburg.

Also i’ll send aerials later of convergent tree damage/structural damage in the occlusion area later.

 

[pohnpei]

The debarking in Monette was impressive, but the tornado also didn’t dig a trench over a foot deep in that area. Seasons do effect the ability for debarking, as well as tree species. The tree damage at Bremen was just as bad as Hackleburg, and Monette. Note the trees at the bottom of this ravine. (Hackleburg 1st pic, Bremen in 2nd). Also keep in mind, Hackleburg caused tree damage to predominantly softwood trees as softwoods are the predominant species in AL as where hardwoods are the predominant species in Kentucky. I’ll also add that the tree damage in Tuscaloosa, and Joplin (which you say they were compared to) where just as bad as Hackleburg.

Also i’ll send aerials later of convergent tree damage/structural damage in the occlusion area later.

I think Mayfield definitely had some intense tree damage but I would be hesitate to say It was as strong as Hackleburg. Hackleburg not only completely debarked softwood, but also hardwood or almost entire forest in many cases.


There were numerous cases of Hackleburg showed perfect symmetrical treefall pattern which is extremely hard for those fast moving tornados. Treefall pattern wasn't that symmetrical for Mayfield which are more typical for spring and winter time tornados. Also I found numerous Cases of Hackleburg showed back convergence of treefall pattern and I only found one place for Mayfield which was in Bremen.

Mayfield had some impressive shurbbery damage like Mayfield factory area, the church in downtown, Cambridge Shore area but such damage was still more common and intense in Hackleburg.

I don't know If trees in winter is harder to debark but it's Interesting to notice Bowling Green/Taylor County/Dresden tornado that day also had similar level debarking of Mayfield. Though these were all violent tornados, I would imagine lesser debarking of them If trees in winter are indeed that hard to debark. Even though trees in winter are indeed harder to debark than spring, It's still hard to make any assumption that Mayfield would did same amount of debarking of Hackleburg If It happened in spring and in Dixie.

Even with these uncertainties, there's still a possiblity that Mayfield was indeed one of the strongest tornados in history, but at least It wasn't as obvious as Hackleburg If we are talking about soild evidence

 

[CalebRoutt]

I think Mayfield definitely had some intense tree damage but I would be hesitate to say It was as strong as Hackleburg. Hackleburg not only completely debarked softwood, but also hardwood in many cases.

There were numerous cases of Hackleburg showed perfect symmetrical treefall pattern which was very hard for those fast moving tornados. Treefall pattern wasn't that symmetrical for Mayfield which is more typical in spring and winter time tornados. Also I found numerous Cases of Hackleburg showed back convergence of treefall pattern and I only found one place in Mayfield which was in Bremen.

Mayfield had some impressive shurbbery damage like Mayfield factory area, the church in downtown, Cambridge Shore area but such damage was still more common and intense
in Hackleburg.

I don't know If trees in winter is harder to debark but it's Interesting to notice Bowling Green/Taylor County/Dresden tornado that day also had similar level debarking of Mayfield. Though these were all violent tornados, I would imagine lesser debarking of them If trees in winter are indeed that hard to debark. Even though trees in winter are indeed harder to debark than spring. It's still hard to make any assumption that Mayfield would did same amount of debarking of Hackleburg If It happened in spring and in Dixie.

Even with these uncertainties, there's still a possiblity that Mayfield was indeed one of the strongest tornados in history, but at least It wasn't as obvious as Hackleburg If we are talking about soild evidence

All good points!

Soil, tree type, etc all have an effect on the appearance of the tree destruction. Since there was hours of prolonged rainfall over northern AL (The 2 MCSs in the morning) the “black convergence” was probably a product of wet soil and scouring opposed to just scouring. I probably should’ve included images from around Cayce where the treefall was very convergent. While there was some debarking in other tornadoes that day, Mayfield (Especially in Monette, Cambridge Shores, Dawson Springs and Bremen) was way worse in terms of intensity because the trees in those areas were not only debarked, but pulled from the ground and thrown a few hundred yards. I don’t think Mayfield was quite as strong (in terms of damage) as 2011 El Reno & Smithville, but the trench/ground scouring & debarking was essentially the same as Philadelphia MS and Hackleburg.

 

[CalebRoutt]

Bowling Green is another tornado I’ll probably do a summary on btw.

 

[MNTornadoGuy]

All good points!

Soil, tree type, etc all have an effect on the appearance of the tree destruction. Since there was hours of prolonged rainfall over northern AL (The 2 MCSs in the morning) the “black convergence” was probably a product of wet soil and scouring opposed to just scouring. I probably should’ve included images from around Cayce where the treefall was very convergent. While there was some debarking in other tornadoes that day, Mayfield (Especially in Monette, Cambridge Shores, Dawson Springs and Bremen) was way worse in terms of intensity because the trees in those areas were not only debarked, but pulled from the ground and thrown a few hundred yards. I don’t think Mayfield was quite as strong (in terms of damage) as 2011 El Reno & Smithville, but the trench/ground scouring & debarking was essentially the same as Philadelphia MS and Hackleburg.

While the trench was impressive I don’t think it was extreme as the one produced by Philadelphia. One reason is that the one produced by Philadelphia was deeper and more extensive than the Mayfield one. Also the second reason is that the Mayfield trenches occurred in a plowed field with weak grass cover which would make the soil weaker. Similar scour holes have occurred in the past such as with the 1964 Gray MS tornado.

 

[CalebRoutt]

There have been many tornadoes to traverse plowed fields that didn’t produce as extensive of a trench as Mayfield. In fact, that’s really the 2nd well documented tornado in the EF-Scale era to cause trenching like that since Philidelphia. Others have but usually it had to do with debris loading over weak fields. The trench was at least a foot, but it’s difficult to tell if that was the deepest portion of the trench or not. Given the nearby tree damage, and perhaps asphalt scouring (not just near the trench but along the whole path) it’s reasonable to say the trench was comparable to 2011 Philadelphia MS.

 

[buckeye05]

Over time, I’ve become less automatically impressed with the trench digging phenomenon seen in some tornadoes. The turning point for me was the EF1 near Mauk, GA on 4/6/2022, which tore up the ground in a similar manner, while causing moderate tree and structural damage.

One can’t deny that they usually seem to be associated with high-end events though.

 

[CalebRoutt]

Over time, I’ve become less automatically impressed with the trench digging phenomenon seen in some tornadoes. The turning point for me was the EF1 near Mauk, GA on 4/6/2022, which tore up the ground in a similar manner, while causing moderate tree and structural damage.

That part of Georgia & into AL is known for having very soft soil types. When considering all other damage from Mayfield it’s actually extremely impressive. I do respect your obstinance though.

 

[tornado examiner]

i still cant believe that in only two scans the mayfield tornado was producing a pronounced, pink, and tight debris ball on reflectivity. btw.....i dont see many people talking about the damage in cayce...tree damage there was pretty nutty...

 

[TH2002]

I will say that as far as ACTUAL "well constructed" homes are concerned, I didn't recall seeing any in Mayfield or in many other places along the path with the exception of Cambridge Shores.

With that said, EF5 damage doesn't have to manifest itself just in the "traditional" homes swept away, and if anything I think seeing a well constructed home swept off its foundation is essentially confirmation that a tornado reached EF5 intensity.

I have always pondered over whether the large, multi-story brick buildings that were leveled in downtown Mayfield could be considered EF5 damage. Off hand I don't know enough about the construction of most of them (though I do strongly feel that one church arguably experienced EF5 damage) though if the destroyed medical arts building in Joplin is considered true EF5 damage, why not the buildings in Mayfield?

Anyways, just my two cents. I really liked the article as much as anyone else, and I'm looking forward to the Bowling Green writeup.

 

[pohnpei]

There have been many tornadoes to traverse plowed fields that didn’t produce as extensive of a trench as Mayfield. In fact, that’s really the 2nd well documented tornado in the EF-Scale era to cause trenching like that since Philidelphia. Others have but usually it had to do with debris loading over weak fields. The trench was at least a foot, but it’s difficult to tell if that was the deepest portion of the trench or not. Given the nearby tree damage, and perhaps asphalt scouring (not just near the trench but along the whole path) it’s reasonable to say the trench was comparable to 2011 Philadelphia MS.

I'm curious was there any close photos of the asphalt scouring damage near the trench? Because the aerial was really ambiguous. And despite the claim that there's asphalt scouring all along the path, I didn't really see a very clear pic. Only one pic from Simon but the road was already refilled.

 

[buckeye05]

I will say that as far as ACTUAL "well constructed" homes are concerned, I didn't recall seeing any in Mayfield or in many other places along the path with the exception of Cambridge Shores.

With that said, EF5 damage doesn't have to manifest itself just in the "traditional" homes swept away, and if anything I think seeing a well constructed home swept off its foundation is essentially confirmation that a tornado reached EF5 intensity.

I have always pondered over whether the large, multi-story brick buildings that were leveled in downtown Mayfield could be considered EF5 damage. Off hand I don't know enough about the construction of most of them (though I do strongly feel that one church arguably experienced EF5 damage) though if the destroyed medical arts building in Joplin is considered true EF5 damage, why not the buildings in Mayfield?

Anyways, just my two cents. I really liked the article as much as anyone else, and I'm looking forward to the Bowling Green writeup.

There’s a big difference from older unreinforced brick, and modern concrete form/CMU structures with a metal frame and reinforcements. The medical arts building was the latter of those two categories.

Also the statement that “any” well-built home being slabbed is confirmation of EF5 isn’t a well thought out way of looking at it, as anchored homes do sometimes fail below the 200 MPH mark, and there’s plenty of examples where context makes this obvious.

It’s easy to really to focus just on the better construction at Cambridge Shores, but the context just wasn’t that remarkable. Sure it tossed cars and debarked trees, but EF4s are more than capable both of those things too. It just doesn’t make the cut context wise, bolts or no bolts.

 

[buckeye05]

In a nutshell, If we had the context from Bremen, and the construction from Cambridge Shores in the same spot, it’d be a clear cut EF5, but we unfortunately don’t have the needed overlap between those two essential criteria along the path.

 

[TH2002]

There’s a big difference from older unreinforced brick, and modern concrete form/CMU structures with a metal frame and reinforcements. The medical arts building was the latter of those two categories.

Also the statement that “any” well-built home being slabbed is confirmation of EF5 isn’t a well thought out way of looking at it, as anchored homes do sometimes fail below the 200 MPH mark, and there’s plenty of examples where context makes this obvious.

It’s easy to really to focus just on the better construction at Cambridge Shores, but the context just wasn’t that remarkable. Sure it tossed cars and debarked trees, but EF4s are more than capable both of those things too. It just doesn’t make the cut context wise, bolts or no bolts.

To clarify, I was NOT trying to say that every well constructed home swept away should be rated EF5. My point is that damage surveys should focus more on contextual damage and other types of structures rather than just homes. If a tornado causes extreme contextual damage and a well-constructed home is swept away to compliment that damage, then yes, it's a clear cut EF5.

This has been said before, but most US homes are constructed like crap and it's pretty much a "matter of chance" as to whether or not a tornado will hit a home capable of indicating such a rating, at peak intensity likewise.

I do have to wonder why the area with the best home construction (Cambridge Shores) had among the weakest contextual damage along the entire path though. Bizarre to say the least.