Severe WX Severe Weather Threat June 6-14

[buckeye05]

A little post-analysis of the Kouts tornado rating decision...

So the main crux of what I was saying was EF4 for Kouts was dependent on the displaced transmission tower, and a forward thinking damage survey team. Unfortunately, while I was correct in thinking that the tower would be the highest rated DI, the survey team played it very "by the book" and did not factor in the proposed updated EF scale's wind speed (170 MPH) for this type of damage to a transmission tower. Some WFO's are very forward thinking and are already factoring in the proposed updates to the scale, such as NWS Norman by utilizing root ball displacements to up the Enid tornado's wind speed estimate. Unfortunately, NWS Chicago does not seem to be particularly forward thinking, and simply went with the maximum possible wind speed for a transmission tower on the current scale, and its obvious this was the thinking based on the DAT comments. My opinion: Not a great call, and not a forward thinking rating decision, but technically correct given the current version of the EF scale. I personally would have gone 170 MPH here.

Now regarding the house, they went with 160. The DAT comments suggest that the house wasn't directly cored by the tornado, and did not suffer the full brunt of the winds within this tornado. The lackluster damage to the trees surrounding this particular home is consistent with that. The fact that the home's entire floor slid off the basement intact, combined with the fact that the house was swept away despite receiving a glancing blow from the tornado suggests that the floor was not properly attached to the basement foundation. My opinion: 160 MPH may seem a little low, but this was actually the right call given the context, obvious floor attachment issues, and glancing blow from the tornado. I might have gone with 165, but that's splitting hairs. High-end EF3 for this particular home is overall appropriate.

Overall conclusion: This tornado probably should have been rated 170 MPH EF4 based on the transmission tower, but they had plenty of basis to call it high-end EF3 given the current guidelines of the scale. Not a forward thinking call, but not unreasonable when the current transmission tower upper bound only goes to 165 MPH. An office like NWS Norman may very well have been gutsy enough to call it EF4 though. NWS Chicago decided to play it by the book however. Oh well.

 

[WeathermanLeprechaun]

A little post-analysis of the Kouts tornado rating decision...

So the main crux of what I was saying was EF4 for Kouts was dependent on the displaced transmission tower, and a forward thinking damage survey team. Unfortunately, while I was correct in thinking that the tower would be the highest rated DI, the survey team played it very "by the book" and did not factor in the proposed updated EF scale's wind speed (170 MPH) for this type of damage to a transmission tower. Some WFO's are very forward thinking and are already factoring in the proposed updates to the scale, such as NWS Norman by utilizing root ball displacements to up the Enid tornado's wind speed estimate. Unfortunately, NWS Chicago does not seem to be particularly forward thinking, and simply went with the maximum possible wind speed for a transmission tower on the current scale, and its obvious this was the thinking based on the DAT comments. My opinion: Not a great call, and not a forward thinking rating decision, but technically correct given the current version of the EF scale. I personally would have gone 170 MPH here.

Now regarding the house, they went with 160. The DAT comments suggest that the house wasn't directly cored by the tornado, and did not suffer the full brunt of the winds within this tornado. The lackluster damage to the trees surrounding this particular home is consistent with that. The fact that the home's entire floor slid off the basement intact, combined with the fact that the house was swept away despite receiving a glancing blow from the tornado suggests that the floor was not properly attached to the basement foundation. My opinion: 160 MPH may seem a little low, but this was actually the right call given the context, obvious floor attachment issues, and glancing blow from the tornado. I might have gone with 165, but that's splitting hairs. High-end EF3 for this particular home is overall appropriate.

Overall conclusion: This tornado probably should have been rated 170 MPH EF4 based on the transmission tower, but they had plenty of basis to call it high-end EF3 given the current guidelines of the scale. Not a forward thinking call, but not unreasonable when the current transmission tower upper bound only goes to 165 MPH. An office like NWS Norman may very well have been gutsy enough to call it EF4 though. NWS Chicago decided to play it by the book however. Oh well.

It does feel like they kinda alluded to this in the DAT text by going "it was the maximum windspeed estimate possible" so one of those situations like Old Kingston 2023 where the office was aware that this was probably a violent tornado but couldn't rate it as such. Difference with this one was that they easily could've/should've but played it by the rules. Wish offices were a bit more gutsy like you said and trying to find ways to actually justify tornado intensity

 

[buckeye05]

It does feel like they kinda alluded to this in the DAT text by going "it was the maximum windspeed estimate possible" so one of those situations like Old Kingston 2023 where the office was aware that this was probably a violent tornado but couldn't rate it as such. Difference with this one was that they easily could've/should've but played it by the rules. Wish offices were a bit more gutsy like you said and trying to find ways to actually justify tornado intensity

Some are, some aren't. That's the unfortunate reality. The updated scale cannot come soon enough.

Also, I just found the fatal flaw for this house that explains why the entire subfloor slid off despite the bolts. While it looked sturdy enough from aerial images, half of the foundation was modern poured concrete, while the other half was flimsy, unreinforced cinder block that completely crumbled. As the tornado impacted the house, the force of the wind pushing against the structure caused the cinder blocks to shift and collapse, which resulted in half of the foundation literally coming apart underneath the house, and subsequently caused the floor to become detached quite easily. I've said it a million times, but when the foundation itself comes apart underneath the bolts, it renders any anchoring pretty much useless. Also context wise, you can see in the last pic that the trees closest to the home lost some branches, but are still standing and aren't debarked, and actually even still have some leaves attached to the branches! This same pic also clearly shows the poured concrete portion of the foundation (left) versus the CMU portion of the foundation (right). This is also why you ABSOLUTELY NEED detailed ground level images to make rating calls. Aerial imagery simply does not show these kinds of details.

However, you can also see that trees farther away from the house are fully stubbed, fully defoliated, and suffered some debarking. This is consistent with the survey team's claim that the house was sideswiped, rather than being directly cored by the tornado. It's insane how tight the wind gradient is here, with moderate tree damage surrounding the home, and more violent looking tree damage on the same property but not immediately next to the house.

 

[WeathermanLeprechaun]

Some are, some aren't. That's the unfortunate reality. The updated scale cannot come soon enough.

Also, I just found the fatal flaw for this house that explains why the entire subfloor slid off despite the bolts. While it looked sturdy enough from aerial images, half of the foundation was modern poured concrete, while the other half was flimsy, unreinforced cinder block that completely crumbled. As the tornado impacted the house, the force of the wind pushing against the structure caused the cinder blocks to shift and collapse, which resulted in half of the foundation literally coming apart underneath the house, and subsequently caused the floor to become detached quite easily. I've said it a million times, but when the foundation itself comes apart underneath the bolts, it renders any anchoring pretty much useless. Also context wise, you can see in the last pic that the trees closest to the home lost some branches, but are still standing and aren't debarked, and actually even still have some leaves attached to the branches! This same pic also clearly shows the poured concrete portion of the foundation (left) versus the CMU portion of the foundation (right). This is also why you ABSOLUTELY NEED detailed ground level images to make rating calls. Aerial imagery simply does not show these kinds of details.

However, you can also see that trees farther away from the house are fully stubbed, fully defoliated, and suffered some debarking. This is consistent with the survey team's claim that the house was sideswiped, rather than being directly cored by the tornado. It's insane how tight the wind gradient is here, with moderate tree damage surrounding the home, and more violent looking tree damage on the same property but not immediately next to the house.

Top notch damage analysis, dude. That's why you're one of the best on here for it.

Your first point is true and unfortunate, it's probably one off the reasons the drought occurred (still can't believe we use past tense for it), but it still is a reason that inconsistencies like this happen. Not to say i have a major problem with this rating but send like some offices are scared to not follow rules and some like the E KY office with London really go thorough and find a reason to give a tornado what it deserves.

 

[buckeye05]

I would also have leaned more towards an EF4 rating for Kouts but there have been plenty tornadoes of similar strength that ended up with EF3 final ratings, which brings back the whole issue of a need for a consistent rating standard between NWS offices. Now the fact that I think it's stupid that apparently past violent tornadoes aren't going to be reexamined using the Enderlin precedent might also have to do with why I'm bringing this up.

I have heard that right now there are no changes being made to past ratings, but in the future that could change. Enderlin was so recent I wouldn't get too frustrated, and I know for a fact that there are influential people both within and outside of the NWS who want to take another look at many questionable ratings from years prior.

 

[Kds86z]

Some are, some aren't. That's the unfortunate reality. The updated scale cannot come soon enough.

Also, I just found the fatal flaw for this house that explains why the entire subfloor slid off despite the bolts. While it looked sturdy enough from aerial images, half of the foundation was modern poured concrete, while the other half was flimsy, unreinforced cinder block that completely crumbled. As the tornado impacted the house, the force of the wind pushing against the structure caused the cinder blocks to shift and collapse, which resulted in half of the foundation literally coming apart underneath the house, and subsequently caused the floor to become detached quite easily. I've said it a million times, but when the foundation itself comes apart underneath the bolts, it renders any anchoring pretty much useless. Also context wise, you can see in the last pic that the trees closest to the home lost some branches, but are still standing and aren't debarked, and actually even still have some leaves attached to the branches! This same pic also clearly shows the poured concrete portion of the foundation (left) versus the CMU portion of the foundation (right). This is also why you ABSOLUTELY NEED detailed ground level images to make rating calls. Aerial imagery simply does not show these kinds of details.

However, you can also see that trees farther away from the house are fully stubbed, fully defoliated, and suffered some debarking. This is consistent with the survey team's claim that the house was sideswiped, rather than being directly cored by the tornado. It's insane how tight the wind gradient is here, with moderate tree damage surrounding the home, and more violent looking tree damage on the same property but not immediately next to the house.

Thanks for this write up. I did see somewhere that the house wasn’t in the core of the tornado path.

 

[Kds86z]

 

[Kds86z]

Don’t think this was posted from last weds.

 

[Grand Poo Bah]

A little post-analysis of the Kouts tornado rating decision...

So the main crux of what I was saying was EF4 for Kouts was dependent on the displaced transmission tower, and a forward thinking damage survey team. Unfortunately, while I was correct in thinking that the tower would be the highest rated DI, the survey team played it very "by the book" and did not factor in the proposed updated EF scale's wind speed (170 MPH) for this type of damage to a transmission tower. Some WFO's are very forward thinking and are already factoring in the proposed updates to the scale, such as NWS Norman by utilizing root ball displacements to up the Enid tornado's wind speed estimate. Unfortunately, NWS Chicago does not seem to be particularly forward thinking, and simply went with the maximum possible wind speed for a transmission tower on the current scale, and its obvious this was the thinking based on the DAT comments. My opinion: Not a great call, and not a forward thinking rating decision, but technically correct given the current version of the EF scale. I personally would have gone 170 MPH here.

Now regarding the house, they went with 160. The DAT comments suggest that the house wasn't directly cored by the tornado, and did not suffer the full brunt of the winds within this tornado. The lackluster damage to the trees surrounding this particular home is consistent with that. The fact that the home's entire floor slid off the basement intact, combined with the fact that the house was swept away despite receiving a glancing blow from the tornado suggests that the floor was not properly attached to the basement foundation. My opinion: 160 MPH may seem a little low, but this was actually the right call given the context, obvious floor attachment issues, and glancing blow from the tornado. I might have gone with 165, but that's splitting hairs. High-end EF3 for this particular home is overall appropriate.

Overall conclusion: This tornado probably should have been rated 170 MPH EF4 based on the transmission tower, but they had plenty of basis to call it high-end EF3 given the current guidelines of the scale. Not a forward thinking call, but not unreasonable when the current transmission tower upper bound only goes to 165 MPH. An office like NWS Norman may very well have been gutsy enough to call it EF4 though. NWS Chicago decided to play it by the book however. Oh well.

This is a great, and excellently explained summary. It's spot on.

I'm still extremely frustrated by this decision though. This was a very high-end event, but since the tornadoes didn't hit anything newly constructed or substantial, it won't be remembered as such. It won't be categorized as an environment that produced violent tornadoes, it won't be included in studies about violent tornadoes, and it won't go in the records as a violent day. Even though it is beyond obvious that it was one. Sure we'll remember it in our hearts, but science will remember it differently.

A 170 mph wind speed is what was easily verifiable based on a glancing blow on a farm house, debarked trees, scoured fields, cycloidal marks, thrown objects, and downed transmission lines.. The tornado easily could've been stronger than that, but it's practically impossible that it was actually an EF3. On the bell curve of wind speeds required for 4 out of 5 damage across a half dozen categories, there's maybe a 5% chance EF3 winds could have caused it. I understand your reasoning for being fine with the rating, and I want to agree with you, but to me it's just plain egregious underrating once again. It's not a "safe" rating, it's a blatantly incorrect one, piled onto dozens of other blatantly incorrect ones from the last decade.

I'm serious. I look at set ups like tomorrow, and I can't help but wonder when the "big one" is going to happen. Sooner or later, an extremely powerful tornado is going to hit a densely populated area, and we're going to find out if 13 years of underrating has any effect on people's perception of the threat. I think about my total lack of understanding of typhoons as someone who doesn't live anywhere close to where they occur, and I wonder if all the foreigners here for the world cup have a similar lack of understanding about tornadoes. When the mesoscale discussion publishes tomorrow and says max intensity of "140-170" will those people understand that what that really means is the potential for 200-300 mph unsurvivable winds that will pulverize everything it touches within seconds? Or will they see it as a high-end typhoon. Scary, but highly survivable.

 

[Grand Poo Bah]

Plus, where the heck is the leadership on this one? We know the new scale rates the transmission line 170. The people leading the development of that scale are also on the QRT and are a readily available resource for these offices. They also are the ones who apparently are required to approve EF4+ ratings and make the final calls on these borderline cases. So why tf are they not making that call? Why is NWS Chicago even being permitted to make EF3 the final rating, when the established science explicitly states it's EF4? My scenarios of the dangers of underrating to human life may be borderline hyperbolic, but the seriously low quality of science being done is maddening enough all on its own. These don't need to be dangerous and life-threatening decisions to be extremely frustrating ones.

 

[buckeye05]

I think the issue is

Plus, where the heck is the leadership on this one? We know the new scale rates the transmission line 170. The people leading the development of that scale are also on the QRT and are a readily available resource for these offices. They also are the ones who apparently are required to approve EF4+ ratings and make the final calls on these borderline cases. So why tf are they not making that call? Why is NWS Chicago even being permitted to make EF3 the final rating, when the established science explicitly states it's EF4? My scenarios of the dangers of underrating to human life may be borderline hyperbolic, but the seriously low quality of science being done is maddening enough all on its own. These don't need to be dangerous and life-threatening decisions to be extremely frustrating ones.

It actually does comes down to playing it cautiously though. The issue is that the 170 MPH rating for transmission towers is something that is proposed, but not set in stone yet. It would be a major slip up if they went ahead and called it 170 MPH EF4, only to have the higher ups renege on extending the transmission tower’s upper bound to 170 MPH. If they roll out the new scale and transmission towers still only go to 165 MPH, NWS Chicago would have egg on their face. We have to keep in mind that the glimpses of the new scale we have seen are glimpses of something that is still being actively tweaked and adjusted. For example, there was a sentiment to get rid of debarking as an indicator, but after Enderlin it’s obvious that this sentiment isn’t really popular or set in stone. Why? Because it’s been established that debarking in rural areas via dirt/sandblasting (“sandpapering” as they called it) is actually a violent tornado indicator.

This whole new scale update is in a constant state of flux. Things are always being adjusted, proposed, added, and removed behind the scenes. So while the addition of extending the transmission tower’s upper bound to 170 MPH logically has some scientific merit and has some precedent, we don’t know if it’s enough to make it to the final draft yet. While I don’t necessarily agree with the rating, I do understand their caution.

Now a whole other can of worms is the tree damage. While the trees immediately next to the swept away home didn’t suffer anything close to violent damage, others on the property did. If the house area sideswiped by the tornado suffered high-end EF3 winds, one could logically infer that the other trees on the property that got cored away from the house and got stubbed/partially debarked experienced EF4 winds. Not all offices have caught on to the whole EF4 tree damage thing yet. I think that will change with time as that idea gets more momentum and acceptance.

 

[buckeye05]

In a nutshell, I can’t fault them too much for going with a 165 MPH EF3 rating. Both potential EF4 damage points involve relatively “new” violent tornado indicators that most surveyors may not register as well…violent tornado indicators. The transmission tower’s upper bound hasn’t officially been extended yet, and many surveyors have to get out of the habit of associating hardwood stubbing/debarking with the EF2-EF3 range, which mind you is a range that debarking still CAN occur in, even though we now know it’s more closely linked to violent tornadoes.