Enhanced Fujita Ratings Debate Thread

[Grand Poo Bah]

the F scales estimation of windspeeds was more accurate. the EF scale has a much wider range of DIs, DODs, as well as better classifying construction and its relation to windspeeds/EF rating

"as well as better classifying construction and its relation to windspeeds/EF rating"

It has completely utterly failed at classifying construction! What are you talking about? It's not very reassuring the best aspect of the EF scale you can come up with is "its accuracy at measuring construction in relation to EF rating". That's like saying a yard stick is the best measuring tool because it measures in yards the best...

"the F scales estimation of windspeeds was more accurate."

Yes, which makes the EF scale a complete failure. Maybe not to insurance companies, or HAAG engineering, but as a tool for the NWS to classify tornado intensity and advance tornado research/science? Completely useless.

 

[joshoctober16]

Can you explain your point a little deeper because this makes zero sense to me. Isn't deriving windspeeds the entire purpose? What else constitutes overall? It can't be damage because the scale doesn't measure damage. It measures construction quality.

i herd in one of the youtube video for the new ef scale that they them self said the whole tree di was garbage or somthing like that (i think it was some sort of sware word) its a long video

 

[joshoctober16]

i herd in one of the youtube video for the new ef scale that they them self said the whole tree di was garbage or somthing like that (i think it was some sort of sware word) its a long video

45:40 in the video , they looked at the ef scale and stated (why did you do that?)

 

[joshoctober16]

What DI’s go up to 220? Is it something other than frame homes? It must have never have been used since the introduction of the scale.

Also, Piedmont got 210+ for the oil rig. If that DI wasn’t enough to get anything above 220 I find it insane that they would give any frame home of any construction, regardless of how slabbed it was, something above 220.

It’s really dumb, something needs to change. Clearly the oil rig required winds well in excess of 210 mph, but I won’t continue to beat the dead horse at this point.

i sware ive seen some other areas list the oil rig as 215 mph damage

 

[Grand Poo Bah]

45:40 in the video , they looked at the ef scale and stated (why did you do that?)

I don't see anything out of the ordinary here and I'd politely ask that you condense your points into less comments please. It's not fair to other commenters when their research gets buried under 8 straight comments from one person. Really appreciate the reddit post you shared and some of your anecdotes though!

 

[joshoctober16]

I don't see anything out of the ordinary here and I'd politely ask that you condense your points into less comments please. It's not fair to other commenters when their research gets buried under 8 straight comments from one person. Really appreciate the reddit post you shared and some of your anecdotes though!

ya perhaps i should of some how merged them all then again i think most were from me replying to others.

 

[Sawmaster]

Can you explain your point a little deeper because this makes zero sense to me. Isn't deriving windspeeds the entire purpose? What else constitutes overall? It can't be damage because the scale doesn't measure damage. It measures construction quality.

Construction quality and wood frame building strength is all over the map, even in places with decent Building Codes inspections. One of today's more popular 'open floorspace' house designs will be far weaker than a more traditional approach with more interior walls even with the exact same build quality. And as I've noted before, fastener type matters a lot but seems to be another overlooked point when engineering rates them all the same. This is why I despise the surveys being so focused on exactness of a listed specification with no leeway allowed for someone noticing these differences- a typical engineer's trait.

There are some natural DI's (defoliation, debarking, scouring, etc) and those also vary by age, health, and species of the plants and soil for scouring, yet they seem to be given less 'weight' in assessing damages. Some of that it being dealt with in the new scale upgrade. Deep scouring certainly rates at the top level regardless of whatever building damage is found, but the focus is on the buildings and natural indicators only used as an adjunct to that. When you reduce something to a series of 'yes or no' checkboxes like is done now, you exclude thinking from the picture and without thinking you get stupid results sometimes. And of you're going to use 'checkboxes' then anyone with normal intelligence and a few hours of training can rate wood frame homes- it doesn't require an Engineer to do that.

I think Dr. Fujita's intent was to differentiate damage with the estimated wind speeds incidental to that because those couldn't be measured accurately at the time. Now that we can measure winds, at least that part needs to be aligned better to damages. And there needs to be an end to any pressure on the surveys regards rating levels. If they're experienced they can rate correctly even if it doesn't quite align with the checkbox standards which engineers are so fond of arguing over.

Which is my main beef. Save for special cases such as the rare oil rig hit where we have few to no comparables, we need to reduce the power of engineering in making rating decisions and replace that with common sense instead.

 

[slenker]

you literally just dont understand how the EF scale works. for a home to get upper bound, it has to be extremely wellbuilt. the intensity of the tornado has nothing to do with it

This is precisely why the EF scale is so counterintuitive though. Why are we applying a windspeed estimate (proportional to the intensity of a tornado) to a scale that is strictly based on engineering? We already have strong evidence that the windspeeds are drastically underestimated when we purely go by the scale’s parameters, yet the current mindset with the scale is to continue to shift the goalpost of EF5 further into impossible territories - despite us having precedent of EF5 level damage not always having to occur with extremely well-built frame homes. (Piedmont, Philadelphia, Joplin)

Cactus was a one of a kind DI, and its complex geometry and countless variables makes it impossible to make an accurate calculation on what windspeeds would be required to topple it. 210< is a fine rating for it

If the calculation was inaccurate, then by today’s standards, it never would have been used as a DI, and the tornado wouldn’t have had another EF5 DI, so it would have been given an EF4 rating, which is pretty egregious imo. I will take a step back on my previous statement stating that it “clearly took winds well in excess of 210 mph” because that may not be true, I didn’t do any calculation here and I’m not a wind engineer. However, if Cactus is a one-of-a-kind DI with unique geometry and inaccurate wind calcs, then a greater effort needs to be made to incorporate clear EF5 tree damage, an example of complex geometry in something that isn’t one-of-a-kind. More specifically, tornadoes like Matador.

 

[Grand Poo Bah]

Another interesting slide from Tim Marshall's presentation "Discriminating EF4 and EF5 Tornado Damage".




He finished the presentation with this home built out of solid concrete, saying if it was destroyed it would exceed the expected wind speeds for damage to a home. Except, I found this picture of the other side of the home....



He's blatantly misleading people.

 

[joshoctober16]

Another interesting slide from Tim Marshall's presentation "Discriminating EF4 and EF5 Tornado Damage".

View attachment 29960


He finished the presentation with this home built out of solid concrete, saying if it was destroyed it would exceed the expected wind speeds for damage to a home. Except, I found this picture of the other side of the home....

View attachment 29958

He's blatantly misleading people.

well to be honest you said if (destroyed) so what even counts as destroyed? all walls down?

 

[TH2002]

***

Another interesting slide from Tim Marshall's presentation "Discriminating EF4 and EF5 Tornado Damage".

View attachment 29960


He finished the presentation with this home built out of solid concrete, saying if it was destroyed it would exceed the expected wind speeds for damage to a home. Except, I found this picture of the other side of the home....

View attachment 29958

He's blatantly misleading people.

That's not a DOD9 or 10 residence. Not elligible for an EF5 rating.

But for what it's worth, the tornado's core just barely missed that dome house, so there is a fair chance it could have sustained EF5 damage had it been a direct hit.

 

[Grand Poo Bah]

***

That's not a DOD9 or 10 residence. Not elligible for an EF5 rating.

But for what it's worth, the tornado's core just barely missed that dome house, so there is a fair chance it could have sustained EF5 damage had it been a direct hit.

I know. I just wanted to highlight the way Marshall bends the truth to mislead people. He deliberately chose to use a picture from the backside of the structure where it was the least damaged, instead of where the building faced the direct force of the winds.

 

[Juliett Bravo Kilo]

Another interesting slide from Tim Marshall's presentation "Discriminating EF4 and EF5 Tornado Damage".

View attachment 29960


He finished the presentation with this home built out of solid concrete, saying if it was destroyed it would exceed the expected wind speeds for damage to a home. Except, I found this picture of the other side of the home....

View attachment 29958

He's blatantly misleading people.

This house was specifically built to withstand up to 200 mph winds, while it wasn't swept away it was severely damaged so it stands to reason that wind speeds in excess of 200 hit it so by the EF scale logic this is EF5 damage. Of course, Marshall managed to twist this around to prove whatever point he wanted to prove, I guess.

 

[slenker]

This house was specifically built to withstand up to 200 mph winds, while it wasn't swept away it was severely damaged so it stands to reason that wind speeds in excess of 200 hit it so by the EF scale logic this is EF5 damage. Of course, Marshall managed to twist this around to prove whatever point he wanted to prove, I guess.

While I do agree that the home experienced EF5 intensity winds (some experts believe that home is a valid indicator of EF5 intensity, despite it not qualifying on the EF scale’s parameters) I don’t think there’s a reasonable way we can calculate the windspeeds there due to the structure only being severely damaged, and it’s not outlandish that HE EF4 did actually impact this location, at least in my opinion.

However, logic should also be used here. This home was outside the core of the path where the most intense damage was located and still dealt with this, so if you do rate this location 200 mph EF4, isn’t it reasonable to assume that EF5 winds occurred away from the structure, and it’s valid to rate it EF5? I don’t see why that’s such a big deal. Scientists are supposed to be pretty conservative, especially for things such as tornadoes, but here the evidence just feels overwhelming.

 

[TH2002]

I know. I just wanted to highlight the way Marshall bends the truth to mislead people. He deliberately chose to use a picture from the backside of the structure where it was the least damaged, instead of where the building faced the direct force of the winds.

Speaking of which, I want to go back to this slide:

I mistook this home for being an alternate angle of the one above, so my mistake. There's scouring by this one (note the dirt piled up against the foundation in the foreground):

But it's a moot point anyways, because here's another angle of the correct home. Definitely scouring here as well:

Whether Marshall made an honest mistake or is deliberately misleading people, I'll leave for other users to speculate.

 

[Grand Poo Bah]

well to be honest you said if (destroyed) so what even counts as destroyed? all walls down?

probably

Speaking of which, I want to go back to this slide:

I mistook this home for being an alternate angle of the one above, so my mistake. There's scouring by this one (note the dirt piled up against the foundation in the foreground):

But it's a moot point anyways, because here's another angle of the correct home. Definitely scouring here as well:

Whether Marshall made an honest mistake or is deliberately misleading people, I'll leave for other users to speculate.

And here's a third photo. Judging by the two photos of the concrete dome, I'd say one simply needs to turn around to see the majority of the scouring. If a home is exceptionally well built, it's fair to assume it acts as some sort of buffer to things downwind until it's swept away. The longer something takes to sweep away, the less things downwind are affected. It's such an obvious conclusion, but it doesn't matter to Tim Marshall. What matters is confusing surveyors to keep them from obvious truths about wind speeds.

He literally just made up the ground scouring context, or the trees 100 yards away, or the shrubs still standing. He's not even consistent because he has underrated slabbed houses with those exact same contextuals multiple times since establishing them. Whoever was making the list of all the excuses used to underrate homes was spot on and I hope they finish it.

Edit:
I keep making bold accusations toward Tim Marshall and it's probably offending some people here. I'll tone it down, sorry. However, after reading all 39 pages of this forum and absorbing it in a short period of time (like a week), the conclusions i'm drawing seem painfully obvious. That's why I'm being so direct.

 

[Shakespeare 2016]

probably

View attachment 29995

And here's a third photo. Judging by the two photos of the concrete dome, I'd say one simply needs to turn around to see the majority of the scouring. If a home is exceptionally well built, it's fair to assume it acts as some sort of buffer to things downwind until it's swept away. The longer something takes to sweep away, the less things downwind are affected. It's such an obvious conclusion, but it doesn't matter to Tim Marshall. What matters is confusing surveyors to keep them from obvious truths about wind speeds.

He literally just made up the ground scouring context, or the trees 100 yards away, or the shrubs still standing. He's not even consistent because he has underrated slabbed houses with those exact same contextuals multiple times since establishing them. Whoever was making the list of all the excuses used to underrate homes was spot on and I hope they finish it.

Edit:
I keep making bold accusations toward Tim Marshall and it's probably offending some people here. I'll tone it down, sorry. However, after reading all 39 pages of this forum and absorbing it in a short period of time (like a week), the conclusions i'm drawing seem painfully obvious. That's why I'm being so direct.

Think about the Westminster 2006 tornado damage survey Tim Marshall and Gary Woodall did. There is no way in hell that the most intense damage done by that tornado was less than high-end F4.

 

[Shakespeare 2016]

Speaking of which, I want to go back to this slide:

I mistook this home for being an alternate angle of the one above, so my mistake. There's scouring by this one (note the dirt piled up against the foundation in the foreground):

But it's a moot point anyways, because here's another angle of the correct home. Definitely scouring here as well:

Whether Marshall made an honest mistake or is deliberately misleading people, I'll leave for other users to speculate.

Correct me if I am wrong but it looks like some anchor bolts were ripped off the slab foundation as well.

 

[TH2002]

Correct me if I am wrong but it looks like some anchor bolts were ripped off the slab foundation as well.

Some of the bolts are definitely gone, most likely snapped off. That could lead credence to the intensity of the tornado itself or a quality issue with the bolts, depending on how you look at it. I've seen snapped anchor bolts considered during both upgrades (Elie) and downgrades (Arabi) so I'm not sure what happened in this case, or if it was even mentioned in the survey report.

 

[crosby]

Why aren't there any instances of said very well constructed homes getting an upper-bound DOD then? We've seen homes with bolts every two feet and specifically designed to be tornado resistant (Goldsby), homes with their interior walls bolted down (Vilonia) and homes that had all of their walls toe-nailed (Moore), and yet they only got the expected DOD or lower despite the superior construction. It brings up the question 'just how well constructed does a home have to be to receive an upper bound rating?' Does it need to be constructed with concrete and titanium or something?

yeah, for a home to get UB it has to be insanely wellbuilt. i dont know the exact specifications required, but to my knowledge, the only 2 tornados ever considered for a UB rating in the EF scale era was one very wellbuilt mansion in hackleburg, and the home that recieved an F5 rating in Elie (F5 rating, but the EF scale was basically used unofficially)