Enhanced Fujita Ratings Debate Thread

[Central Ohio Wx]

Regular Radar or something like DOW/RAXPOL? The sample size for DOW/RAXPOL is going to be very small. That may end up actually upgrading, just estimating, 1-2 tornados every five years?

I’m thinking of DOW/UMassXPOL/RAXPOL/etc; I’d be against using velocity scans on NEXRAD as a metric of strength on its own. There have been countless tornadoes that have had very strong couplets but have ended up being quite weak, with the Robinson tornado from a few days ago being a great example.

 

[slenker]

Regular Radar or something like DOW/RAXPOL? The sample size for DOW/RAXPOL is going to be very small. That may end up actually upgrading, just estimating, 1-2 tornados every five years?

The two I can really think of are El Reno and Greenfield. However, those weren’t necessarily “borderline” EF4/EF5 damage wise. I’m sure the committee has worked a lot of this out behind the scenes though.

If El Reno 2013 is good enough to bump up to EF5 based on the radar measurements, a bump to EF5 for Greenfield is inarguable in my eyes - I'd argue that Greenfield at the moment does have a very small argument for EF5 based on damage due to the parking stop throws, similar in magnitude to Joplin's case of parking stop throws, and Ethan Moriarty concluded that EF5 winds were required at very low AGL to throw them the way it did.

Of course, that's just one engineer's calculations for the objects. Assuming the calculations are fully valid, since it was just one instance of structural damage pointing to EF5 over a very confined area, a good argument against it becomes similar to why Rolling Fork didn't get the rating. It just wasn't enough.

Since I'm no engineer and am not an expert in any universe here, my opinion isn't worth a whole lot in this conversation - but I gotta say, I don't think I can support giving El Reno 2013 an EF5 rating at the moment, even with the radar measurements taken into account. I'm highly skeptical of it being able to inflict true EF5 damage to a structure. It may be quite unfair for me to say that since there was very little debris in the path, but I feel like the ground damage would have certainly been more extreme if it was capable of doing such a thing. If it is given an EF5 rating, I'd be happy to mend my views on it with more in-depth explanations from those who do end up re-rating it, if it does happen.

 

[CheeselandSkies]

If El Reno 2013 is good enough to bump up to EF5 based on the radar measurements, a bump to EF5 for Greenfield is inarguable in my eyes - I'd argue that Greenfield at the moment does have a very small argument for EF5 based on damage due to the parking stop throws, similar in magnitude to Joplin's case of parking stop throws, and Ethan Moriarty concluded that EF5 winds were required at very low AGL to throw them the way it did.

Of course, that's just one engineer's calculations for the objects. Assuming the calculations are fully valid, since it was just one instance of structural damage pointing to EF5 over a very confined area, a good argument against it becomes similar to why Rolling Fork didn't get the rating. It just wasn't enough.

Since I'm no engineer and am not an expert in any universe here, my opinion isn't worth a whole lot in this conversation - but I gotta say, I don't think I can support giving El Reno 2013 an EF5 rating at the moment, even with the radar measurements taken into account. I'm highly skeptical of it being able to inflict true EF5 damage to a structure. It may be quite unfair for me to say that since there was very little debris in the path, but I feel like the ground damage would have certainly been more extreme if it was capable of doing such a thing. If it is given an EF5 rating, I'd be happy to mend my views on it with more in-depth explanations from those who do end up re-rating it, if it does happen.

Maybe I've missed/forgotten seeing any others, but the TWISTEX Colbalt (RIP) was among the worst-damaged vehicles from El Reno I've seen and even that didn't quite reach the threshold of what I think of as high-end violent tornado vehicle damage (stripped to the frame or crumpled into an unrecognizable ball).

 

[Central Ohio Wx]

Maybe I've missed/forgotten seeing any others, but the TWISTEX Colbalt (RIP) was among the worst-damaged vehicles from El Reno I've seen and even that didn't quite reach the threshold of what I think of as high-end violent tornado vehicle damage (stripped to the frame or crumpled into an unrecognizable ball).

It definitely didn't:

This is not EF5-caliber vehicle damage. There is an argument to be had for El Reno being EF4 170 based off structural damage, but I haven't seen any evidence it went higher than that outside of radar, which I explained a few months ago with Greenfield to be unreliable for accurate intensity depending on circumstances.

I could easily see both the back and front damage due to it being rolled vertically (crumple zones in the front will also make damage look worse than it is); the left side of the body is relatively undamaged outside of debris or rolling dents which tells me it's really not that violent of an indicator. The biggest thing it has going for it in terms of the rolling is that I don't see mud or anything blasted around it; if it had been rolled very hard there probably would've been a lot of mud. So who knows, maybe it's wind-caused.

 

[Grand Poo Bah]

If El Reno 2013 is good enough to bump up to EF5 based on the radar measurements, a bump to EF5 for Greenfield is inarguable in my eyes - I'd argue that Greenfield at the moment does have a very small argument for EF5 based on damage due to the parking stop throws, similar in magnitude to Joplin's case of parking stop throws, and Ethan Moriarty concluded that EF5 winds were required at very low AGL to throw them the way it did.

Of course, that's just one engineer's calculations for the objects. Assuming the calculations are fully valid, since it was just one instance of structural damage pointing to EF5 over a very confined area, a good argument against it becomes similar to why Rolling Fork didn't get the rating. It just wasn't enough.

Since I'm no engineer and am not an expert in any universe here, my opinion isn't worth a whole lot in this conversation - but I gotta say, I don't think I can support giving El Reno 2013 an EF5 rating at the moment, even with the radar measurements taken into account. I'm highly skeptical of it being able to inflict true EF5 damage to a structure. It may be quite unfair for me to say that since there was very little debris in the path, but I feel like the ground damage would have certainly been more extreme if it was capable of doing such a thing. If it is given an EF5 rating, I'd be happy to mend my views on it with more in-depth explanations from those who do end up re-rating it, if it does happen.

@GrenadinesDes also discovered a well built home with anchor bolts and toe nails that was completely swept away in Greenfield, so that definitely could add some evidence to the EF5 case. Apparently it was missing nuts and washers though so who knows. Unfortunately it looks like the pics he uploaded are broken and I never saved them. It's incredible how many houses have not nuts and washers. It makes no sense.

I emailed NWS Des Moines about this swept away home that went unrated, but they haven't responded. So I want to personally rate the home and see what it would most likely get if it was officially rated. This was a three bedroom home built in 1996. Home not too old. On the tweet that originally posted the photos and videos of this home, the top comments had people believing this was EF5 damage, considering this was taken during the whole Greenfield EF5 hype, but this home suffers from several problems.

Structurally:
1. The one story home had a large garage that was facing towards the tornadic winds
2. Most of the sill plates remained on the foundation.
3. It seems like a couple of the anchor bolts are missing proper nuts and washers
Contextually:
1. The home directly right to the swept home only suffered EF1 damage
2. A tree, while knocked over, wasn't debranched/debarked.

Some positive to point out is that the anchor bolts seem to be properly spaced out and the sill-plates were toenailed. Personally, this home would get rated EF4/175. With the range between 165-175 mph.

Site is fixed! I'm not sure if it's just me, but it looks like your pics got broken somehow. Maybe you can edit your comment and re upload? That'd be appreciated because I never got them downloaded

The EF scale accounts for attached garages, so I don't think that should be a reason for going below the expected wind speed for slab swept clean.

View attachment 49242

Here's a further zoomed out shot of the house from Jordan Hall's drone video. As you can see there are several trees debarked and denuded in the immediate vicinity.

View attachment 49243

If you zoom out further you can see the EF1 house to the right and complete utter destruction on the left

View attachment 49244

The best explanation for the house on the right is that this tornado had one of the craziest damage gradients you will ever see. It was an absolute drillbit.



This just leaves the missing nuts and washers, which is definitely significant if true. My only question is --and I hope someone here can answer this-- if the bolts were missing nuts and washers then how did they get bent? Wouldn't the sill plate have just slid right off?

 

[Central Ohio Wx]

It's incredible how many houses have not nuts and washers.

Being a tornado enthusiast has really made me realize how scummy or just overall bad construction companies can be at their job. Does someone have a photo of that one home hit by the Locust Grove EF3? It's literally some of the worst construction I have ever seen.

 

[Grand Poo Bah]

I hate to be negative in response to the exciting news about re rating, but I do not even remotely buy what Tim Marshall is saying. He is the one who argued the most against using DOW measurements for ratings, and is a big reason why offices stopped using them in the first place. Now, with no new evidence, he is reversing his decision and says they're good to go again? This is 100% the result of public pressure, and the fact that DOW measurements are the biggest thing casual weather nerds shout about in regards to underrating. Allowing them to be considered again does absolutely nothing to fix this broken system. He is conceding El Reno to protect his a$$, and avoid a bigger audit of all the terrible ratings he's been involved in.

As long as Tim Marshall is the de facto leader of tornado ratings no real progress can be made towards fixing them. He's repeatedly proven himself to be acting in bad faith, and he's gotta go.

All that being said, i'm hugely and enthusiastically in support of your project @buckeye05. I think it's a fantastic idea and am really excited to see how it goes. I think there's plenty of WFOs who will be eager to receive the evidence you compile and open to your arguments. Looking forward to helping out any way I can.

 

[Grand Poo Bah]

Being a tornado enthusiast has really made me realize how scummy or just overall bad construction companies can be at their job. Does someone have a photo of that one home hit by the Locust Grove EF3? It's literally some of the worst construction I have ever seen.

Yeah it's wild to me that the most mild of inconveniences (going and buying washers and bolts) is enough to stop builders from permanently harming the quality and strength of a home in a significant way forever. Difficult to wrap my mind around and I'm surprised more construction companies aren't caught in the act.

 

[ColdFront]

I hate to be negative in response to the exciting news about re rating, but I do not even remotely buy what Tim Marshall is saying. He is the one who argued the most against using DOW measurements for ratings, and is a big reason why offices stopped using them in the first place. Now, with no new evidence, he is reversing his decision and says they're good to go again? This is 100% the result of public pressure, and the fact that DOW measurements are the biggest thing casual weather nerds shout about in regards to underrating. Allowing them to be considered again does absolutely nothing to fix this broken system. He is conceding El Reno to protect his a$$, and avoid a bigger audit of all the terrible ratings he's been involved in.

As long as Tim Marshall is the de facto leader of tornado ratings no real progress can be made towards fixing them. He's repeatedly proven himself to be acting in bad faith, and he's gotta go.

All that being said, i'm hugely and enthusiastically in support of your project @buckeye05. I think it's a fantastic idea and am really excited to see how it goes. I think there's plenty of WFOs who will be eager to receive the evidence you compile and open to your arguments. Looking forward to helping out any way I can.

I hear your overall point and agree with some of it, but I do want to slightly push back on the Marshall stuff.

After hearing what I heard on WeatherBrains, it sounds like at least part of the drought wasn’t overzealous structural engineers or Tim Marshall acting as the EF5 tyrant (which both aforementioned parties have been guilty of during the drought). Part of it was actually just this insane web of government agencies and checks these local WFOs have to go through to give a tornado an EF5. I’m really convinced now most WFOs would rather rate a tornado a 4 and go on their way rather than call in forensic engineering and do all these meetings. That’s all independent of Tim. Of all the flaws of the EF scale, I didn’t realize how much the government itself could impede these ratings being handed out.

 

[TH2002]

Maybe I've missed/forgotten seeing any others, but the TWISTEX Colbalt (RIP) was among the worst-damaged vehicles from El Reno I've seen and even that didn't quite reach the threshold of what I think of as high-end violent tornado vehicle damage (stripped to the frame or crumpled into an unrecognizable ball).

It definitely didn't:
View attachment 50802
This is not EF5-caliber vehicle damage. There is an argument to be had for El Reno being EF4 170 based off structural damage, but I haven't seen any evidence it went higher than that outside of radar, which I explained a few months ago with Greenfield to be unreliable for accurate intensity depending on circumstances.

I could easily see both the back and front damage due to it being rolled vertically (crumple zones in the front will also make damage look worse than it is); the left side of the body is relatively undamaged outside of debris or rolling dents which tells me it's really not that violent of an indicator. The biggest thing it has going for it in terms of the rolling is that I don't see mud or anything blasted around it; if it had been rolled very hard there probably would've been a lot of mud. So who knows, maybe it's wind-caused.

El Reno '13 did utterly mangle a few vehicles. I'd say these cars probably experienced EF5 level winds above the ground, but I doubt said winds ever reached ground level. These vehicles and the DOW/RAXPOL readings are the only indicators of EF5 intensity from this tornado.

 

[Central Ohio Wx]

El Reno '13 did utterly mangle a few vehicles. I'd say these cars probably experienced EF5 level winds above the ground, but I doubt said winds ever reached ground level. These vehicles and the DOW/RAXPOL readings are the only indicators of EF5 intensity from this tornado.

Interesting. I thought I had seen something similar to the second pic obliterated, but I couldn't remember if it was from El Reno or not. I'll look more into it in a bit as obviously my El Reno knowledge isn't great.

 

[akt1985]

Speaking of nuts and washers, I remember hearing on the recent Weather Brains podcast the reason the homestead where the fatalities occurred in the Enderlin tornado was assigned an EF4 rating despite evidence of nuts and washers in the structure was due to the granulation of debris at the homestead.

 

[Central Ohio Wx]

Being a tornado enthusiast has really made me realize how scummy or just overall bad construction companies can be at their job. Does someone have a photo of that one home hit by the Locust Grove EF3? It's literally some of the worst construction I have ever seen.

It was this one:

Who installed the walls?? A view from the front does it zero justice; one wall just plopped over.

 

[buckeye05]

I hate to be negative in response to the exciting news about re rating, but I do not even remotely buy what Tim Marshall is saying. He is the one who argued the most against using DOW measurements for ratings, and is a big reason why offices stopped using them in the first place. Now, with no new evidence, he is reversing his decision and says they're good to go again? This is 100% the result of public pressure, and the fact that DOW measurements are the biggest thing casual weather nerds shout about in regards to underrating. Allowing them to be considered again does absolutely nothing to fix this broken system. He is conceding El Reno to protect his a$$, and avoid a bigger audit of all the terrible ratings he's been involved in.

As long as Tim Marshall is the de facto leader of tornado ratings no real progress can be made towards fixing them. He's repeatedly proven himself to be acting in bad faith, and he's gotta go.

All that being said, i'm hugely and enthusiastically in support of your project @buckeye05. I think it's a fantastic idea and am really excited to see how it goes. I think there's plenty of WFOs who will be eager to receive the evidence you compile and open to your arguments. Looking forward to helping out any way I can.

Thanks, it could be slow going and genuine results are not a guarantee, but it’s worth a shot if presented the right way.

With that said, finding a way to gather a negative takeaway and response to objectively good news is crazy work, especially given the highly speculative basis for your stance here. I can guarantee you that Tim Marshall has no investment in “appeasing” anyone. You did the same thing after Jim LaDue’s recent presentation in which he proposed a less conservative approach to damage surveying (a gripe related to lack of accountability for previous years of bad ratings, and somehow hearing his verbal support for responding to Lyza’s findings as a problematic statement). This is a topic where you take whatever forward progress you can get, and that’s all there is to it. When things start moving in the right direction, it really doesn’t matter who it’s coming from or what they said or did previously.

 

[TH2002]

It was this one:
View attachment 50811
Who installed the walls?? A view from the front does it zero justice; one wall just plopped over.

Yeah... that home is definitely a head-scratcher. The anchoring of the sill plates to the slab is actually quite good... a mix of anchor bolts and plate straps, and the sills remained attached as expected. As for how the walls failed so spectacularly... yeah, I mean the studs are straight nailed, but even then, straight nailed studs shouldn't fail THAT badly. In some of the photos the nails are definitely rusted, with some of them even snapping, so that may have played a role. Maybe they used the wrong kind of nails for connecting the wall studs to the sill plates. Whatever the case, clearly a major issue with wall stud connections, and an example of why the presence of anchor bolts alone does NOT automatically equal better construction.

I guess I could see an argument for low-end EF3 for this house... but tbh, this is one of the rare instances where I think the surveyors going EF2 despite wall loss isn't a horrible call.

 

[slenker]

El Reno '13 did utterly mangle a few vehicles. I'd say these cars probably experienced EF5 level winds above the ground, but I doubt said winds ever reached ground level. These vehicles and the DOW/RAXPOL readings are the only indicators of EF5 intensity from this tornado.

When the car damage is discussed from this tornado, I always tend to see the Cobalt and that previously led me to believe that the EF3 rating was entirely valid, since this particular instance of damage would max out at a 170 EF4 IMO. Ever since I saw these images (which I believe you previously shared here, after I asked a question about its most impressive DIs, lol) my opinion changed to "still not quite EF5 IMO, but I definitely could be convinced."

But, just now, looking at Enderlin's EF5 rating, it really does have a similar level of ground damage overall to El Reno '13, perhaps a smidge more intense. And Enderlin was 1000% an EF5, outside of the train throw it literally disappeared the building that had fatalities in it. Intense rootballing was observed, and the while the tree damage wasn't necessarily what I would call slam-dunk EF5, it was certainly intense enough to be in the HE EF4 range. That falls within the error of EF5 well enough too for me to just state it, especially with the context of the other DIs. (I'm stating this because I see some people online still doubting Enderlin's EF5 rating, even after it was officially given...)

Honestly, after comparison with Enderlin's EF5 rating, I've changed my mind officially. El Reno 2013 probably does deserve an EF5 rating, but I will say that Enderlin was definitely more intense than El Reno. I imagine if El Reno '13 went through a populated area, we'd see damage similar in vein to Joplin, perhaps over an even wider area. Unsure if it would match its intensity though.

 

[CheeselandSkies]

El Reno '13 did utterly mangle a few vehicles. I'd say these cars probably experienced EF5 level winds above the ground, but I doubt said winds ever reached ground level. These vehicles and the DOW/RAXPOL readings are the only indicators of EF5 intensity from this tornado.

Yeah, I had either missed seeing those before, or forgotten I had. That definitely fits the bill; hard to even tell those were once automobiles without a second (or third) look. Just based on those I could see going with EF4, perhaps even high-end. I might still have a hard time applying EF5 solely based on passenger automobile damage.

 

[Central Ohio Wx]

Honestly, after comparison with Enderlin's EF5 rating, I've changed my mind officially. El Reno 2013 probably does deserve an EF5 rating, but I will say that Enderlin was definitely more intense than El Reno. I imagine if El Reno '13 went through a populated area, we'd see damage similar in vein to Joplin, perhaps over an even wider area. Unsure if it would match its intensity though.

What makes El Reno so unique and hard to quantify intensity-wise is the fact that it was basically multiple small violent tornadoes within a huge circulation. I know this isn't damage-related but just look at this screencap:

I think if it had gone through, say, Warr Acres (where it was roughly aiming for before it lifted) I think the damage would've been uncomparable to anything we've seen - there would've been multiple defined sub-vortex areas that would have probably been in the EF4-EF5 range. Enderlin was just one monster wedge with a defined center.

 

[Lake Martin EF4]

I think the damage would've been uncomparable to anything we've seen

Is this "the damage patterns would be unprecedented because it was effectively 5 violent tornadoes working as a team instead of one single circulation" or "Jarrell shakes in its boots"? Or both?

 

[Central Ohio Wx]

Is this "the damage patterns would be unprecedented because it was effectively 5 violent tornadoes working as a team instead of one single circulation" or "Jarrell shakes in its boots"? Or both?

The former. Jarrell is a very solid contender for being the strongest ever recorded; I think if El Reno had tracked into Warr Acres it would've been basically what you said: multiple violent tornadoes in a cycloidal motion going through a large town. It's impossible to compare with Jarrell as we both don't know the damage that El Reno's subvortices would've caused at peak intensity, and the fact that both were opposite in several ways - Jarrell had one extremely violent core, whereas El Reno had multiple violent circulations but no real "core" in a traditional sense.

Put simply, the damage pattern would have possibly been extremely erratic in terms of where damage would've been caused, and something which has almost never been observed in an urban/suburban setting besides maybe Sneed 1929 (we don't have many images of damage from that event though).