• Welcome to TalkWeather!
    We see you lurking around TalkWeather! Take the extra step and join us today to view attachments, see less ads and maybe even join the discussion.
    CLICK TO JOIN TALKWEATHER

Severe WX December 10 & 11, 2021 Severe Threat

This is going to be remembered as one of the most spectacular nighttime videos of a violent tornado ever taken. The only ones that come close are some of the videos taken of the Garland/Rowlett, TX EF4, which was actually another December event.
I wasn't even thinking about Rowlett. The tornado in Nathan Moore and Bryan Valdez's video was fully lit the entire length of it. I reckon all the lights from the Dallas Metro was really what helped illuminate that one so well.
 
Video was taken by chaser, Michael Gordon. I'm in awe of this footage. It's about as up close and clear of a shot as anyone could get of a violent nighttime tornado.
Obviously this was on a whole other level, but this video reminds me so much of some of the descriptions I've been given of the 5/31/85 Moshannon F4. The size/structure, the forward speed, the inky blackness of the funnel as it's backlit. Absolutely horrifying for the people who had to experience it, but extraordinary to see captured so well on video.
 
I mean I’d assume analysis is still ongoing, and there’s no reason to believe up close examination didn’t take place. I just hope they aren’t playing ridiculously conservative and we end up with multiple EF3s that should have been rated EF4. I definitely have some concerns about NWS Louisville’s surveying tendencies.

Anyone know what the last EF4 was in their CWA? I think it might have been Henryville.
Having the same feeling with you, seems like Louisville has already completed surveying the Saloma KY tornado and just rated it low-end EF3
b39db35308b08809.jpg
 
It bothers me immensely that things have gone from slabbed and swept home = EF5 to slabbed and swept home = EF3 unless it was an impossibly overbuilt fortress without even a single shred of anything to give an excuse to hold it that low AND occurring in a CWA whose maximum possible rating is more than EF3. If no home along the path meets 'average' home construction on the slider to warrant an appropriate rating then seems like the definition of 'average' needs to change because no home seems to meet it anywhere by survey standards. Doesn't seem so average if it can never be met
 
It bothers me immensely that things have gone from slabbed and swept home = EF5 to slabbed and swept home = EF3 unless it was an impossibly overbuilt fortress without even a single shred of anything to give an excuse to hold it that low AND occurring in a CWA whose maximum possible rating is more than EF3. If no home along the path meets 'average' home construction on the slider to warrant an appropriate rating then seems like the definition of 'average' needs to change because no home seems to meet it anywhere by survey standards. Doesn't seem so average if it can never be met
Well, in theory, the EF scale ought to rate those houses accurately based on the wind speed necessary to cause the damage. If a certain type of damage can be caused by winds below the EF5 threshold, then I can't really fault them for not going higher with the rating.

Maybe the answer is just to not rate tornadoes categorically and use the estimated wind speed as the sole way of rating them. The categorization is kind of arbitrary anyway.
 
What are these NWS offices trying to prove by rating literally EVERY tornado from this outbreak as an EF3 or "at least an EF3"? I understand with some tornadoes like Bowling Green it's an OK starting point, but with tornadoes like Caruthersville and Bremen where the extremely violent contextual damage is literally right in your face, why not just go preliminary EF4?
 
Well, in theory, the EF scale ought to rate those houses accurately based on the wind speed necessary to cause the damage. If a certain type of damage can be caused by winds below the EF5 threshold, then I can't really fault them for not going higher with the rating.

Maybe the answer is just to not rate tornadoes categorically and use the estimated wind speed as the sole way of rating them. The categorization is kind of arbitrary anyway.
The problem is this (quite often) doesn't really occur.
 
Well, in theory, the EF scale ought to rate those houses accurately based on the wind speed necessary to cause the damage. If a certain type of damage can be caused by winds below the EF5 threshold, then I can't really fault them for not going higher with the rating.

Maybe the answer is just to not rate tornadoes categorically and use the estimated wind speed as the sole way of rating them. The categorization is kind of arbitrary anyway.
Clearly most houses can be wiped out well below EF5, but that brings up the question of how we want to use EF5 to begin with; if the most utter and complete destruction possible only warrants an low EF4 without a level of home construction that 99% of the country never meets then why even have a higher number available that's impossible to reach; also many WFOs seem to have decided violent tornadoes don't exist and refuse to even top EF3 for damage that clearly warrants it for unknown reasons

Another big problem is that historical tornadoes that are clearly vastly overrated remain on the books for doing far less even as recently as 20 years ago; F4-5 ratings for shifting a single house off their foundation and collapsing them (which would be perhaps generously mid EF3 damage) inspires no confidence in the historical record and the over conservative tendency now to nitpick and low-ball makes the discrepancy even more stark

I am thrilled we get extensive surveying and wind engineering analysis, for sure, and surveys are fascinating, but I think there's a fundamental problem with the final application of the scale to rate it moreso than with the construction integrity conclusions.
 


In the Bowling Green area, scouring very evident and a large home completely destroyed with a considerable amount of wind rowing.

If NWS Louisville keeps everything at EF3 or below when this is all said and done, it’s going to erode my remaining trust for that particular WFO when it comes to surveys, and I’m going to have to consider them another MEG or SGF from this point onward. Damage from several of the tornadoes within their WFO from this outbreak is more intense than the supposed “EF4 damage” in Newnan, GA earlier this year. That speaks volumes.
 
Clearly most houses can be wiped out well below EF5, but that brings up the question of how we want to use EF5 to begin with; if the most utter and complete destruction possible only warrants an low EF4 without a level of home construction that 99% of the country never meets then why even have a higher number available that's impossible to reach; also many WFOs seem to have decided violent tornadoes don't exist and refuse to even top EF3 for damage that clearly warrants it for unknown reasons

Another big problem is that historical tornadoes that are clearly vastly overrated remain on the books for doing far less even as recently as 20 years ago; F4-5 ratings for shifting a single house off their foundation and collapsing them (which would be perhaps generously mid EF3 damage) inspires no confidence in the historical record and the over conservative tendency now to nitpick and low-ball makes the discrepancy even more stark

I am thrilled we get extensive surveying and wind engineering analysis, for sure, and surveys are fascinating, but I think there's a fundamental problem with the final application of the scale to rate it moreso than with the construction integrity conclusions.
Yeah, I don't know if there's a good way to reconcile historical tornado rankings with current ones, given that they were based on looser standards and a less realistic assessment of wind speeds. It's not really possible to go back and re-rate them according to current standards, so even if you managed to create more consistent/realistic assessments in the present, it's not going to solve the problem of historical comparisons.
 
If NWS Louisville keeps everything at EF3 or below when this is all said and done, it’s going to erode my remaining trust for that particular WFO when it comes to surveys, and I’m going to have to consider them another MEG or SGF from this point onward. Damage from several of the tornadoes within their WFO from this outbreak is more intense than the supposed “EF4 damage” in Newnan, GA earlier this year. That speaks volumes.
Should note that area has not been surveyed yet.
 
Yeah, I don't know if there's a good way to reconcile historical tornado rankings with current ones, given that they were based on looser standards and a less realistic assessment of wind speeds. It's not really possible to go back and re-rate them according to current standards, so even if you managed to create more consistent/realistic assessments in the present, it's not going to solve the problem of historical comparisons.
Then people really need to stop pretending a modern EF rating is even remotely comparable to what its F scale rating would have been; I hear everywhere people swearing that the ratings are 1:1 equal but the vast discrepancies in construction analysis before and after the development of the EF scale makes any historical comparison completely impossible and we can legitimately throw out any rating before 2003-ish.

There really isn't a way to accurately re-rate historical tornadoes and it's frustrating that pre 70s ratings - done by university students with no experience doing so through old photos at the behest of Fujita and others - are even remotely taken seriously
 
Brett Adair is currently in the Bremen area, and it looks like just about every house in the core of the damage path there got slabbed or very near it.

 
Then people really need to stop pretending a modern EF rating is even remotely comparable to what its F scale rating would have been; I hear everywhere people swearing that the ratings are 1:1 equal but the vast discrepancies in construction analysis before and after the development of the EF scale makes any historical comparison completely impossible and we can legitimately throw out any rating before 2003-ish.

There really isn't a way to accurately re-rate historical tornadoes and it's frustrating that pre 70s ratings - done by university students with no experience doing so through old photos at the behest of Fujita and others - are even remotely taken seriously
Yeah, I think that's a fair point. I have no problem with just saying "look, there's no way we can reconcile the two ratings scales, let's not pretend they're equivalent". As a historian, I find the idea of not having a consistent historical record annoying, but I don't think there's a way we can make those comparisons with any rigor. It's hard to say we should just throw out half a century of data, but if that data was based on bad assessments, I don't know how you can fix it retroactively.
 
Yeah, I think that's a fair point. I have no problem with just saying "look, there's no way we can reconcile the two ratings scales, let's not pretend they're equivalent". As a historian, I find the idea of not having a consistent historical record annoying, but I don't think there's a way we can make those comparisons with any rigor. It's hard to say we should just throw out half a century of data, but if that data was based on bad assessments, I don't know how you can fix it retroactively.
I guess it's probably a good thing the EF scale came when it did so at least the F ratings are consistently iffy and the EF ratings are subject to a little more realism... now if only we could get rid of WFO to WFO inconsistency and the notion that "as conservative as humanly possible = most accurate" then the F to EF inconsistency could be our only unsolvable problem lol
 
Back
Top