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I might buy that reasoning if the ratings were tied to empirically-confirmed wind speeds rather than estimates, since you could actually come to more concrete (no pun intended) conclusions about how much time a tornado would have to remain over an area to cause a certain category of damage. But when it's all estimated anyway, that seems arbitrary to me.
Rainsville was extremely violent in its own right, but gets overshadowed by Philadelphia, Hackleburg, and especially Smithville. The thing about Rainsville is that it was rated EF5 mainly based on contextual damage. Surveyors were understandably very hesitant about upgrading based on this, so it wasn’t upgraded from EF4 to EF5 until June. The homes it swept away, while anchor-bolted, had cinder block foundations rather than poured concrete or slabs, so the structural damage it produced wasn’t quite as impressive as Smithville or Hackleburg. However it did manage to:

-Obliterate a stone house, ripping a pillar and a large concrete anchor out of the ground.
-Rip concrete porches out of the ground, shattering them and scattering concrete fragments for over 100 yards.
-Scour grass and pavement, and pull sidewalk out of the ground.
-Scour earth from over top of an underground storm shelter, heaving up upward out of the ground slightly.
-Rip an 800 lb engineered “EF5 proof” Liberty Safe from its bolts, throwing it 600 feet and ripping the steel door from its hinges.

All of this clearly points to EF5 winds, though the actual structural damage wasn’t quite as impressive. For this reason, Rainsville’s EF5 rating is well-deserved, though a bit liberal considering how the EF5 scale is typically used.
Though there was very little to no EF5 structural damage with the Rainsville tornado, I remember reading the survey and the contextual evidence blew my mind.
 

pohnpei

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What are your guys thoughts on the Rainsville EF5 of 4/27/11? Seems to be less talked about than Smithville, Hackleburg, and Philidelphia at least from what I've seen.

Isn't Rainsville the one that ripped up an 800lbs safe that was bolted in concrete and tossed it?

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It seems the EF5 rating of Rainsville mainly based on the damage alone Lingerfeldt Road, especially this house below. It was mentioned in NWS that a large two story brick home was completely obliterated with several of the supporting anchors ripped out of the ground, so I suppose it was quite well constructed? But it also seemed the slab itself wasn't sweep that clean. The famous anchored liberty safe damage happened there which was really impressive.
rainsville.jpg
When tornado getting close to Sylvania, some damage can be found in this video


I would say there was no clear EF5 evidence around this area. The tree damage clearly not on the same page with Hackleburg/Smithville/Bassfield.
 
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Rainsville was extremely violent in its own right, but gets overshadowed by Philadelphia, Hackleburg, and especially Smithville. The thing about Rainsville is that it was rated EF5 mainly based on contextual damage. Surveyors were understandably very hesitant about upgrading based on this, so it wasn’t upgraded from EF4 to EF5 until June. The homes it swept away, while anchor-bolted, had cinder block foundations rather than poured concrete or slabs, so the structural damage it produced wasn’t quite as impressive as Smithville or Hackleburg. However it did manage to:

-Obliterate a stone house, ripping a pillar and a large concrete anchor out of the ground.
-Rip concrete porches out of the ground, shattering them and scattering concrete fragments for over 100 yards.
-Scour grass and pavement, and pull sidewalk out of the ground.
-Scour earth from over top of an underground storm shelter, heaving up upward out of the ground slightly.
-Rip an 800 lb engineered “EF5 proof” Liberty Safe from its bolts, throwing it 600 feet and ripping the steel door from its hinges.

All of this clearly points to EF5 winds, though the actual structural damage wasn’t quite as impressive. For this reason, Rainsville’s EF5 rating is well-deserved, though a bit liberal considering how the EF5 scale is typically used.
I'll add that the consistency of wind rowing was impressive and it did leave some gnarly tree damage
rainsvillewindrow.png
6499255781_fafab3a3c0_b.jpg
though the structural damage weirdly isn't that impressive at this residence. It did have a very complex multi-vortex damage pattern.
 

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pohnpei

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Rainsville was extremely selective, but the few instances of extreme damage it did were among the most powerful ever recorded. Extreme Planet has a pretty good write-up on Rainsville, which I had to link through the Wayback Machine as his domain has expired:

Yes, his article was wonderful to read. The selective pattern of its damage was interesting. It did violent car damage while the structure damage nearby was at EF2-3 level and it did EF5 house damage while the tree nearby was largely intact and it did EF5 level tree damage while the house nearby wasn't at the same level.
 
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pohnpei

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Rainsville was extremely selective, but the few instances of extreme damage it did were among the most powerful ever recorded. Extreme Planet has a pretty good write-up on Rainsville, which I had to link through the Wayback Machine as his domain has expired: https://web.archive.org/web/2017042...5-damage-in-rainsville-alabama-april-27-2011/

A few notable photographs:

These 2 photographs are of the 800 pound Liberty safe that was anchored to the foundation of a home, ripped and thrown a significant distance into the woods nearby with its door removed and the cab of the pickup thrown 250 yards from 1608 Lingerfeldt Road, the largest piece of the vehicle remaining.

View attachment 3879View attachment 3880

This was a school bus:

View attachment 3881

Severe vegetation damage, tree debarking and ground scouring north of Rainsville and pavement scouring near Sylvania.
View attachment 3882
So it was intereting to talk about when there was inconguity among the struture damage, vegation damage and vehicle damage in one place, which one is more important to judge the true intensity of the tornado in this place? These kinds of problem always exist when we differentiate betwenn EF3 or EF4 damage and EF4 or EF5 damage. They may take different priority in different situations, largely, the vegetation damage and the structure damage are more imprtant than other things in my opinion.
 
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Rainsville left high end DODs all over the place but it happened over an area where there weren't many structures that were properly anchored. But you've got ground scouring, completely debarked trees, extreme vehicle damage and wind rowing/debris granulation over many miles. In lieu of the classic EF5 sweeping of a well constructed home, those things should be substituted. Especially when they occur over a wide area.
 

pohnpei

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And speaking of these kinds of incongurity, I may have some different points of Greensburg tornado 2007. We know that the tree damage of this tornado was much impressive than the structure damage inside the town like this picture below showed. Many large hardwood trees were largely to completely debarked which is typically to see in EF5 level tornado. But the EF5 level structure damage inside the town was very sporadic strangely.
In my understanding, tornadic winds was much easier to make strong structure damage than straight line winds. In other word, it takes less winds to do the same structure wind for tornadic winds than straight line winds. So, I suppose that the tornado with very small RMW was more easily to do structure damage than the tornado with very largre RMW. The RMW of tornado was typiclly vey small, so it didn't matter in most cases when we compare the intensity of different tornados. But Greensburg had the widest EF4 damage smath that ever surveyed since EF scale put into effect, much larger than the second widest one on this list(Joplin MO), showing the RMW of this tornado must be very large just like what we see in the detection of Mulhall and El Reno 13 tornado by DOW/RaxPol radar. The Discussion of RMW of Mulhall tornado written by Joshua Wurman and his team was recommand to read on this topic.He said torando this large was similar to a mini tropical cyclone.
So as to say, to every singel house inside the town, the proportion of straight line winds was much larger than the vertical winds compared to tornados with smaller RMW. Despite the potential longer duration of the torando to each single house, the proportion of the tornadic winds(or just vertical winds to say more precisely)was much important otherwise the Guiuan, Philippines should be completely wipe out of the surface in 2013 by Typhoon Haiyan with peak gust winds almost certainly much higher than 200mph at north eyewall.
QQ图片20200704132330.jpg
Guiuan, Philippines
5 Guiuan5.jpg5 Guiuan4.jpg
 
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pohnpei

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Another case was the high end EF4 house damage of Bassfield tornado.It seemed that there were incongruity between the tree damage and the structure damage at this point. Despite the clear slab of a well constructed house it made, the tree debarking was not that impressive. But I'm still not convinced of that.
It should be noted that the house was not at the center line of the tornado. In these kinds of tornado with very large circulation but very tiny core, just like Typhoon Hagibis and Hurricane Patricia in terms of tropical cyclone, even 10-20m makes big difference.
The tree damage in front of the house was normal with little evidence of debarking showed in the picture below.
QQ截图20200606212827.jpg
QQ图片20200704140634.png
But when we closer to the center of the path, it was easy to tell that the tree damage become much severe :
QQ截图20200704142610.jpg
It was cleared that these trees was at the downwind direction of the debris of the house, before that, the tornado was at the open field. So there was little to no debris to debark these trees. In spite of this, it was still considerably debarked amazingly. And also noted that the tree most near the tornado center was almost dismantled and being unrecognizable with mud covered from the ground. Consideting the feature of this very small core and very fast movement of the tornado, it must be destroyed like this within a few seconds. These kinds of tree damage was not typically at all for EF4 level tornados and I would suppose that the winds near the center of the tornado was stronger than the winds hit that house based on the huge difference of the tree damage.
Besides, the grass around the house was not soured was also easy to understand: beacuse it was not at the center of the path.
QQ截图20200606212525.jpg
QQ截图20200606212337.jpg
After passing this area, the tornado was very likely still stengthening and made that famous increible tree damage thereafter.
QQ图片20200704144412.png
The sources of these pictures was screen captured in videos that have already been posted by buckeye05 in main discussion thread.

 
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buckeye05

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Hmmm. I’m kinda on the fence about what I think Bassfield’s rating should be at this point. An argument for high-end EF4 can technically be made due to some relatively minor structural flaws, a likely vehicle impact, and the only slabbed, well-anchored home along the path not being directly within the swath of EF5-consistent contextual damage.

However, I have come to strongly suspect that the Bassfield tornado briefly reached EF5 intensity, with a small swath of EF5 winds extending from the area where the anchored home/cabin was slabbed, to nearby Willie Fortenberry Road, where ground scouring and remarkable tree damage/debarking occurred, and multiple vehicles were carried hundreds of yards and mangled.

So I do understand why they went with EF4, but overall I feel that a small swath of EF5 winds did indeed occur, albeit briefly. I don’t know how well that sits with me.
 

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A wonderful report on the Smithville tornado that NWS MEG could only hope to replicate.

Very brilliant writing and I only has one single question: Did the three Red SUV pic posted in the article really the same one? I'm a little confused because it didn't look like the same car(not equal size?) but I can be wrong.
 

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Here are two papers on the development and strengthening of El Reno tornado on May 24, 2011. I have a bold point of view, but maybe I'm wrong. We all know that before the El reno tornado, the mother storm of El reno produced lookeba Ef3. The tornado was powerful enough to flatten many parts of fr12. So my idea is that the two tornadoes, lookeba and El reno, are only likely to undergo morphological changes or short-term upgrades, because according to this paper, the cycle between the two tornadoes only takes four minutes. In such a good environment, the tornado cycle will not be so fast, because the tornado is in balance between the inflow and outflow, and coincides with the rising center. If the tornado decays rapidly and moves behind the mesocyclone, it can only be said that the cold pool suddenly strengthens to a certain extent. However, due to the influence of the cold pool, the vorticity and updraft cannot be vertical. If the cold pool is too strong, it may directly cut off the storm inflow, which may not lead to the formation of the next tornado. However, from another point of view, the strengthening of cold pool will lead to morphological changes and visibility increase, and the outflow of cold pool will stimulate other storms. Another paper also points out that the combination of the new mesocyclone formed between the cold pool storm and the parent rainstorm is also the reason for the rapid development of the low-level cyclone and the rapid strengthening of the El Reno tornado
 

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Dang, that tornado was probably like manna from heaven for chasers after the atrocities of May and June. One event that's piqued my attention is the Brackettville, TX F4 of May 16, 1989. If you haven't heard of it, you're not alone. There's very little evidence of this tornado's existence aside from its presence in official databases and May 16 as a whole has been largely forgotten. There's some
footage of an HP supercell further north in the panhandle on Sam Barricklow's website and a youtube video with some snippets of TWC coverage of the day. I apologize in advance for the lack of photos, but that's the nature of this tornado.

Meteorologically speaking, May 16th was a fairly classic synoptically evident set up for the TX panhandle. A strong neutral/slightly pos tilt trough centered over the desert SW(AZ/NM border roughly) was pushing west, with an attendant deepening low and sharp dryline. Divergence in the jet was expected to support supercell structures in the panhandle and, with all that it mind, the NSSFC(precursor to SPC) issued a high risk for the OK/TX panhandles and western Oklahoma. For the most part, the high risk area underperformed, though an HP supercell(documented on Sam Barricklow's site) did produce a few tornadoes, including one F2, near the Bushland, TX area. It seems that unexpectedly weak llvl winds and the best instability being displaced from the lowest LCL's prevented the day from reaching its full potential in the Panhandle/W OK region.

As the dry line retreated toward the TX/Mexico border, drawing moister air westwards, low level winds increased substantially throughout Texas and surface winds began to back SE to ESE around the Brackettville area. As temperatures dropped throughout the evening, LCL heights responded accordingly, dipping below 1000m in the area. The responsible supercell initiated across the border near Del Rio, TX, an area that is apparently pretty ripe for violent supercell/tornado production. The Piedras Negras/Eagle Pass, TX EF4/EF3 in April 2007 and Ciudad Acuna EF4 in May 2015 were spawned in the same area west of the Sierra Madre mountain range. The complex topography in the region likely plays a role in promoting some of the insane supercells we see down there, similar to the Rockies and the western plains states.

The responsible supercell crossed into Texas and began producing a tornado at approximately 11:08CT just to the south of Brackettville. It moved generally to the east for about 6 miles, sliding underneath Brackettville, at an unspecified lower-end intensity. Past the town the tornado began to deviate to the left, taking on a NNE motion and intensifying quite rapidly to its maximum intensity. Mesquite trees were snapped at ground level, debarked/denuded, and in some cases ripped out of the ground and thrown considerable distances. 40 yards of pavement was scoured from US 90 as the storm passed overhead and substantial ground scouring occurred over "a long stretch of the path", though the degree of scouring is unspecified and undocumented. The maximum damage intensity occurred over 6 miles of mostly uninhabited ranch land and only three homes, residing outside the most intense corridor of damage, were destroyed. The F4 rating was assigned almost exclusively due to the extensive tree damage and the ground/pavement scouring left behind. The tornado then began to turn back to the right(NNE to NE), producing F0-F1 damage for another 6 miles before dissipating.

A few hours later the same supercell would go on to produce the first, lesser known Jarrell, TX tornado, killing 1 and leaving widespread F3 damage in the area. Unlike most higher-end tornadoes in that area of SW to C Texas, the Brackettville F4 produced violent damage while moving at highway speed. It covered 20 miles over a span of 22 minutes, so roughly 50-60mph. Almost all of this information comes from a small blurb in the May 89 edition of Storm Data which, in contrast to the entry on the Bakersfield Valley storm a year later, features no damage photographs. Just a satellite image, a path map, and a rather vague description of the damage. I'm left wondering how intense it truly was and if it might've approached the ungodly intensity of the Bakersfield Valley F4. Unlikely, but certainly possible given the impressive damage descriptions and the dearth of reliable documentation.


All information sourced from:
https://www.ncdc.noaa.gov/IPS/sd/sd.html
https://www.spc.noaa.gov/exper/outbreaks/#
http://www.k5kj.net/19890516.HTM
 
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Dang, that tornado was probably like manna from heaven for chasers after the atrocities of May and June. One event that's piqued my attention is the Brackettville, TX F4 of May 16, 1989. If you haven't heard of it, you're not alone. There's very little evidence of this tornado's existence aside from its presence in official databases and May 16 as a whole has been largely forgotten. There's some
footage of an HP supercell further north in the panhandle on Sam Barricklow's website and a youtube video with some snippets of TWC coverage of the day. I apologize in advance for the lack of photos, but that's the nature of this tornado.

Meteorologically speaking, May 16th was a fairly classic synoptically evident set up for the TX panhandle. A strong neutral/slightly pos tilt trough centered over the desert SW(AZ/NM border roughly) was pushing west, with an attendant deepening low and sharp dryline. Divergence in the jet was expected to support supercell structures in the panhandle and, with all that it mind, the NSSFC(precursor to SPC) issued a high risk for the OK/TX panhandles and western Oklahoma. For the most part, the high risk area underperformed, though an HP supercell(documented on Sam Barricklow's site) did produce a few tornadoes, including one F2, near the Bushland, TX area. It seems that unexpectedly weak llvl winds and the best instability being displaced from the lowest LCL's prevented the day from reaching its full potential in the Panhandle/W OK region.

As the dry line retreated toward the TX/Mexico border, drawing moister air westwards, low level winds increased substantially throughout Texas and surface winds began to back SE to ESE around the Brackettville area. As temperatures dropped throughout the evening, LCL heights responded accordingly, dipping below 1000m in the area. The responsible supercell initiated across the border near Del Rio, TX, an area that is apparently pretty ripe for violent supercell/tornado production. The Piedras Negras/Eagle Pass, TX EF4/EF3 in April 2007 and Ciudad Acuna EF4 in May 2015 were spawned in the same area west of the Sierra Madre mountain range. The complex topography in the region likely plays a role in promoting some of the insane supercells we see down there, similar to the Rockies and the western plains states.

The responsible supercell crossed into Texas and began producing a tornado at approximately 11:08CT just to the south of Brackettville. It moved generally to the east for about 6 miles, sliding underneath Brackettville, at an unspecified lower-end intensity. Past the town the tornado began to deviate to the left, taking on a NNE motion and intensifying quite rapidly to its maximum intensity. Mesquite trees were snapped at ground level, debarked/denuded, and in some cases ripped out of the ground and thrown considerable distances. 40 yards of pavement was scoured from US 90 as the storm passed overhead and substantial ground scouring occurred over "a long stretch of the path", though the degree of scouring is unspecified and undocumented. The maximum damage intensity occurred over 6 miles of mostly uninhabited ranch land and only three homes, residing outside the most intense corridor of damage, were destroyed. The F4 rating was assigned almost exclusively due to the extensive tree damage and the ground/pavement scouring left behind. The tornado then began to turn back to the right(NNE to NE), producing F0-F1 damage for another 6 miles before dissipating.

A few hours later the same supercell would go on to produce the first, lesser known Jarrell, TX tornado, killing 1 and leaving widespread F3 damage in the area. Unlike most higher-end tornadoes in that area of SW to C Texas, the Brackettville F4 produced violent damage while moving at highway speed. It covered 20 miles over a span of 22 minutes, so roughly 50-60mph. Almost all of this information comes from a small blurb in the May 89 edition of Storm Data which, in contrast to the entry on the Bakersfield Valley storm a year later, features no damage photographs. Just a satellite image, a path map, and a rather vague description of the damage. I'm left wondering how intense it truly was and if it might've approached the ungodly intensity of the Bakersfield Valley F4. Unlikely, but certainly possible given the impressive damage descriptions and the dearth of reliable documentation.


All information sourced from:
https://www.ncdc.noaa.gov/IPS/sd/sd.html
https://www.spc.noaa.gov/exper/outbreaks/#
http://www.k5kj.net/19890516.HTM
This is really interesting stuff, I do wonder if Doswell may have some info on this thing, as he seems to know quite a bit about obscure tornado events in Texas (he also, at least I think, has quite a bit of information on the June 1995 Texas Panhandle outbreak (the one responsible for the Pampa, Hoover, Allison and Kellerville storms). Really interesting that Jarrell has had other tornadoes hit it and that TX had a tornado moving in the 50-60 mph range, usually you only see those kind of forward speeds in Dixie Alley.
 
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This is really interesting stuff, I do wonder if Doswell may have some info on this thing, as he seems to know quite a bit about obscure tornado events in Texas (he also, at least I think, has quite a bit of information on the June 1995 Texas Panhandle outbreak (the one responsible for the Pampa, Hoover, Allison and Kellerville storms). Really interesting that Jarrell has had other tornadoes hit it and that TX had a tornado moving in the 50-60 mph range, usually you only see those kind of forward speeds in Dixie Alley.
Perhaps he might. He actually chased the high risk area that day up near Amarillo. I wanna say Fujita himself surveyed the Brackettville track though or at least someone in close contact with him. Texas Tech's library has a pretty extensive collection of Fujita's original photographs/notations so I'd think that would be the place to look(shaking my head because I lived there not too long ago.)I've done quite a bit of research on it and come up empty though. Even local news outlets barely acknowledge its existence. Yeah, that kind of storm motion is highly unusual for that area. A lot of the big boys down there are lumberers that deviate to the SE and then go nuts, while this one did the exact opposite.
 
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eric11

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I reviewed some video clips from the Wilkin co.MN EF4(Also known as Tyler ND EF4)on 8/7/2010 and found that this one shares exact same characteristics with Dalton MN EF4,drillbit shape,violent and tight motion,extraordinary cornfield scouring,occurred on rural farmlands,narrowly missed or hit one or two poorly anchored farmsteads.I've once heard that the EF4 rating given to wilkin was based on the ground scouring,but we all know ground scouring has never been considered as DI and ground scouring is such a multivariate indicator that we seldom rank it as the first when it comes to official tornado intensity determination.And from some perspective,I can't really tell which one was stronger,It seems that wilkin has more remarkable ground scouring and vegatation but Dalton's vehicle damage was absolutly insane.Dalton got more violent motion and spin-ups. but considering photographers'distance and video quality,If wilkin happens today,it may achieve the same motion.The following are some damage pics I collected from wilkin MN EF4 on 8/7/2010,EF4 strength undoubtfully
2e240ffa1d88f180.jpg-6c2ac71c9c2e6201.jpg41cf872532ec36a8.jpg-2c328d345b734a85.jpg-5f032334cbea6b8192b0daaedc565ba2.jpg-7c73255cafd373549889b69d2535c220.png-52022363f1c50e38c93aad7787037bdb.jpg37108f5ebfec61b1e274aae52f1acf4c.jpg-760c1fa29bdd41f1b141322c10e9ca53.jpg-4da7bb2edd8d27954a7f7d8044c01eeb.jpg-7c73255cafd373549889b69d2535c220.png
 
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