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Enhanced Fujita Ratings Debate Thread

N0mz said:
Do you have the slide with the DODs up to 13? Gave me a heart attack making me think that EF5 wasn't possible on FR12 anymore
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i dont sadly , that is what they only showd for now , but in a different area shows DOD13 is swept clean

20241022_065244.jpg

thats all i have of now

1751552182088.png
Gray:not shown but known to exist
light Red:new DOD
Dark Red:new DOD but hasn't been shown

note im not sure if this not shown DOD is number 11 or 12 ,
 
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N0mz said:
Do you have the slide with the DODs up to 13? Gave me a heart attack making me think that EF5 wasn't possible on FR12 anymore
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however .... Stronger then Typical resistance might not be possible anymore (sorta)

im unsure if they mean they cant put it to 205 or if they mean they cant put it to 240 (as in fully in stronger then typical resistance) however this new rule is if it isnt in the hurricane prone areas... then it at least wont get a 240 mph rating (unsure about 205-235 mph)

Framehouse Resistance.png

note ONLY ONE F5 has ever went in this hurricane prone area
 
1751552873370.png

from what i can tell the new EF scale has

2 bad updates
2 mix updates
8-9 good updates

i remember listening to one of the video about the next EF scale... and they stated they are forcing all the mph to end with a 0 or 5 mph ... i wouldnt have a issue with this... if it wasnt for the reason they stated...

they wanted to make all the 1 mph off from the next rating to be gone... however what they did... is make this 1 mph off from the next rating... worse and more common.

interestingly both bad updates can simply be fix if they make each EF rating mph start in a 0 or 5 mph zone.... (only EF0 has this)
 
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joshoctober16 said:
View attachment 44790

from what i can tell the new EF scale has

2 bad updates
2 mix updates
8-9 good updates

i remember listening to one of the video about the next EF scale... and they stated they are forcing all the mph to end with a 0 or 5 mph ... i wouldnt have a issue with this... if it wasnt for the reason they stated...

they wanted to make all the 1 mph off from the next rating to be gone... however what they did... is make this 1 mph off from the next rating... worse and more common.

interestingly both bad updates can simply be fix if they make each EF rating mph start in a 0 or 5 mph zone.... (only EF0 has this)
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Have they discussed factoring in contextuals?
 
joshoctober16 said:
no , and they are removing tree being debarked as a DOD , they will now be ignoring that.
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Wha??? That's stupid; that's one of the few viable DIs out of powerful rural tornadoes. I can already tell this scale isn't going to fix the issues we currently have if they end up removing trees as a DI.
 
joshoctober16 said:
however .... Stronger then Typical resistance might not be possible anymore (sorta)

im unsure if they mean they cant put it to 205 or if they mean they cant put it to 240 (as in fully in stronger then typical resistance) however this new rule is if it isnt in the hurricane prone areas... then it at least wont get a 240 mph rating (unsure about 205-235 mph)

View attachment 44789

note ONLY ONE F5 has ever went in this hurricane prone area
Click to expand...
I feel like those lower than expected rules are brutal
 
OH-IOan said:
Wha??? That's stupid; that's one of the few viable DIs out of powerful rural tornadoes.
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a confusing thing about rural tornadoes i notice is ... they seem proud and all happy to show di29 ... acting as if its going to fix all the rural issue.... and its just this...

1751554109996.png

what i find to be important di , would be any common di that has a typical resistance of 150+ mph

i mean... yeah its better to have it then not but ... not helpful if it cant go above 150 mph
 
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OH-IOan said:
Wha??? That's stupid; that's one of the few viable DIs out of powerful rural tornadoes. I can already tell this scale isn't going to fix the issues we currently have if they end up removing trees as a DI.
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they only remove tree debark , not the trees them self's , infact they combined and split the 2 tree di into 2 different di.

the other new di can sometimes be rated EF5

Screenshot_3.png

its sorta a improvement its just ... they did one big negative ....

overall what i would find to be a perfect tree di would be
1:tree debark is back
2:EF5 single tree (at least for strong)
3:Add small tree (theres mid and big)
4:split the bodily removal DOD7 into 4 (and in the <25% , 25% , 50% , 75%) like what they did for everything else.

i would then find it a perfect tree di if these 4 things would be added/changed
 
OH-IOan said:
Also, when is this scale expected to go into effect? I've seen people discuss it for a while but I don't know if they have a set "release date" yet
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Probably another few years. They’re still having to vote on certain parts of it in the different committees.

This was one of Doswell’s original criticism of the EF scale. No one really “owns it”, so an ad hoc group has to be put together across multiple fields and disciplines. I imagine the glacial pace is just due to the amount of people involved, as well as getting a large group of scientists to agree on anything.
 
Aaron Rider said:
Tylertown was more violent than I initially thought.

Please understand: I am not saying this tornado deserved to be rated higher. I am just genuinely curious because the DAT description is scanty. This is from the EF4 rated damage.

Here's what the DAT says: "Well built two story home. Wood bolted to foundation. Some bolts pulled off of foundation. Found some clips but most of the damage is thrown behind the house and inaccessible."

That's ambiguous, though. Did the bolts shear or did the concrete shear out? Was the anchoring reasonable? By contrast, in my opinion anyway, the photos from Diaz seem to show a clear anchoring performance indicating the structural connections held until the bolts themselves couldn't handle the wind load (note that the washers were still present in the case of the badly sheared Diaz bolts).

The far right anchor bolt in the first picture is clearly deformed, but not as badly as Diaz. I'm guessing sill plate failure was the dominant failure mode, though? (which is less extreme than the Diaz case)

The images are too big, so here are the links

Hard to grade context from this, but it does look closer to old school F4 than F5, IMO.

Here are the 3 pictures on the DAT. Again, I just want to know if anyone knows more about why they stuck with EF4. Am I on the right track in assuming that there was some sill plate failure + lower context in the judgment? Anyway, it was definitely a very, very violent tornado.
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N0mz said:
Here's the slideshow its ripped from: https://training.weather.gov/wdtd/courses/EF-scale/lesson2/presentation_html5.html (module 17)

A better screenshot:
View attachment 44769
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Bumping these two comments together because holy excrement. Look at how much anchors with clips supposedly improve wind resistance. If Tylertown actually had an anchored home with clips that was swept away we've got a serious EF5 contender.
 
Grand Poo Bah said:
Bumping these two comments together because holy excrement. Look at how much anchors with clips supposedly improve wind resistance. If Tylertown actually had an anchored home with clips that was swept away we've got a serious EF5 contender.
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I’ve said it before, but there was an image posted of some really incredible tree damage from the Tylertown, MS tornado. Like, very high end. I’ll need to find it.
 
Debarking is often a clear indicator of violent environment even if it cannot pin down an *exact* wind speed. If trees are fully debarked and stubbed, and if it's paired with ground scouring and structure obliteration, it still indicates violent winds. Dismissing it entirely removes a vital environmental clue.

Note: context matters!

Tree debarking will not move a rating today from EF3 → EF4 or EF4 → EF5 unless paired with high-quality structural failure evidence (or, if they're being extremely nitpicky, not at all!). So why is it even necessary to remove such an indicator?

Using “debris loading” as a blanket excuse to discard tree debarking as a violence indicator is overcorrection. It should caution surveyors to consider the cause, not dismiss the indicator entirely.

Sorry, but instead of taking things into consideration on a case by case basis, this strikes me as more unnecessary and lazy conservatism. Why are they afraid of contextual analysis?

Controlled testing and field studies have, I'm sure. shown debris can strip bark at lower winds than required for direct aerodynamic debarking. I'm sure they'll say that, and ignore how Fujita said "Extraordinary phenomena will occur" (stuff like extreme, Bridge Creek debarking)....stuff hard to explicate or replicate. But debris loading is not usually sufficient on its own to fully debark large trees around their entire circumference or create the smooth, sandblasted appearance seen in EF5 contexts. That's why I'm willing to be completely unimpressed with this change.
 
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