Enhanced Fujita Ratings Debate Thread

[joshoctober16]

The new EF scale looks like 8 steps fowards , 2 steps in place and 2 steps back.

lets start with the good

1:Frame house have been split into 2
2:metal building systems have been sub split into (non hurricane zone and hurricane zone)
View attachment 22216
3:the 2 mobile home di have been merged
View attachment 22217
4:tree fall pattern(forest damage or multi-tree) di added (helpful to stop underrating tornadoes)
5:Farm silos and grain bins have di (farm silos helpful for less underrated tornadoes)
6:center pivot irrigation system is now di
7:Wind Turbines di added
View attachment 22223
8:radar ratings can be used?
(this one is not 100% sure but it looks like it will be in, unsure how it will look like
9:frame houses wind speed make more sense for the poor/strong build ones
View attachment 22224


that is all the big good things the new EF scale will be able to do, there are a bunch of other smaller good updates , and 2 that are kind of.... both a upgrade and downgrade?

il try to find the 3-4 sources i got this from

 

[joshoctober16]

https://www.researchgate.net/public...rent_Revision_of_the_Enhanced_Fujita_EF_Scale

here is 3 of them , theres a other il post later after i explain the wierd 2 new negetive and 2 semi positive-negetive parts of the new scale

 

[joshoctober16]

and now for the 2 new negatives
1:they are forcing all the wind speed to be 0 or 5 (as in 65 mph , 70 mph, 75 mph) this will cause a lot of 1 mph from its next EF(Number).
(interestingly they stated they did this so it would stop having 1 mph off from the next rating.... what they did makes it worse...)


2chance of no more EF5 in non hurricane prone areas.

(note no official f5/ef5 have ever happened here meaning more anti EF5 rating)
however its to note unsure if they mean they just cant rate it as a 240 mph tornado (example 230 mph instead) or that if it or it means it gets shoved with just 200 mph
while what counts as a framehouse hurricane prone region map isnt shown the Mobile home hurricane prone region is shown


and how to fix both of this is kind of simple

just do this, you instantly get rid of both problems with this one small fix.

its to note that EF5 are still the only rating that has no common typical expected rating, as the highest one (at least that i can see) is 200 mph, therefor i suggest changing EF5 to 200 mph OR completely removing EF5 ratings as keeping a EF rating in a hard to get jail as unrealistic.

they need to make it possible to have a EF5 rating that is from one of these DI and must be in the typical strength range
DI 2 - Wood-Framed Residences (WFR): (200 MPH Typical Resistance)
DI 3 - Concrete Block Residences (CBS): (?)
DI 7 - Passenger Vehicles (PV): (165 MPH Typical Resistance)
DI 9 B - Farm Silos (FSGB): (200 MPH Typical Resistance)
DI 21 A - Metal Building Systems (MBS): (?)
DI 21 B - Metal Building Systems-Hurricane Zone (MBS): (?)
DI 27 - Single Tree (TREE): (155 MPH Typical Resistance)
DI 28 - Multi-Tree (MT): (170 MPH Typical Resistance)

as you can see 3 are still not shown to the public, and all the ones shown don't go to 200 mph with their Typical Resistance

the Di i picked were pick for this reason...


there are 3 options for nws
1:lower the bar and at least have one common typical DOD be possible for EF5
2:keep it above the bar and make the data trash for looking into studies about tornado patterns, and also cause a lot of online drama (bad and what nws seems to want)
3:Remove EF5 to get rid of all this mess if they are so scared of rating a tornado EF5 (better then option 2)

it is to note for NWS that 95+ % of past tornadoes that got rated F5 would not be rated EF5 today, its stressful to see people say that all the worst tornadoes are going away while they are still here, we just made the bar too high to rate them, this is making a artificial EF5 drought, and its best that all past and present F5/EF5 to be around the same starting destructive level.

 

[joshoctober16]

and extra semi mention that is sorta part of a negative, the thing is its a negative that is still a old problem as in

1:Missing DoD type for some buildings (broken or missing foundation, and again it has happened)
2:missing DoD that the original F scale seem to mention (EF5 single tree damage)
3:still too hard to get EF4 and EF5 damage overall (EF4 is a bit better thought)
4:missing di types (18 wheeler, soil scouring, manhole covers)

these are all problems but are not really a NEW negatives

Next is about the 2 Di that seem to be both a positive and a negative the same time.... the 2 odd ones (there are other odd things but there not as odd as these 2)

 

[joshoctober16]

and now for the semi negetive or semi positive new parts of the new EF scale...

1:the single tree damage is reworked.
good 1:merged the softwood and hardwood into one
good 2:has a subtype di of mid size and large tree size
good 3:new dod of removal of the tree and being thrown.

bad 1:no small tree size
bad 2: dod4 and dod5 have the same wind speed for any resistance and subtype....
bad 3: tree debarking has been removed.....
bad 4: no typical resistance EF5 damage



the funny story is what they stated about the old DOD.... the tree experts stated:why did you do that?
this is in the other video il try to look for its original source.

2:Car di added
good 1: the fact this di is added
good 2: helpful to stop underrating tornadoes

bad 1: only di that is honestly trash....
bad 2:no Typical EF4 dod
bad 3:no cars being completely mangled
bad 4:no thrown 100+ meters
bad 5:no thrown 1000+ meters or 1 km
bad 6:no thrown 1+ mile away
bad 7:there is no weaker then typical resistance
bad 8:there is no stronger then typical resistance
bad 9:dod2 , dod3, dod4 are all 110 mph.... like why....
bad 10:dod5 and dod6 are both 165 mph ....



my god what happened when making this one? this is the only one i honestly find feels like a joke

2 other to note that kind of have 2 problems are

1:multi tree's last di should be split into 4 and should be in 25% increment like how they made it for all other DI

top is how it is currently
bottom is how it should be


2:no stronger then typical resistance for farm silos


everything else is a positive or not changed.

i feel like they perfected mobile homes at least.

next is to find that other video presentation that 70% of all the info came from

 

[joshoctober16]

most of the info comes from the video above
the video under migth show the map for the hurricane prone area?





... also why did one of my prev post got one of its text changed into a emoji....

 

[buckeye05]

Sorry I’ve been out of the loop, but unless I’m misunderstanding one of those above tables, is tree damage now EF5 eligible!?

 

[joshoctober16]

Sorry I’ve been out of the loop, but unless I’m misunderstanding one of those above tables, is tree damage now EF5 eligible!?

i guess? but i was expecting it to be single tree and not multi tree , but then again only strong trees, also semi off topic of the new EF scale, i think i know why they removed debarking, as the IF scale shows it would take 230+ mph winds to do that... for average.... strong and weak trees.... (note its for 60+% debarking) heres the IF tree scale
note that IF5 starts at 292 mph , the weird sign beside the IF4 you see for DOD 9 means at or above IF4 , meaning according to the IF scale any image of a complete debarked tree is EF5 damage, or IF4-IF5 damage, and knowing nws being all anti EF5 i can see why they removed debarking now, it would make EF5 common.

however i do feel they should slightly lower 60+ % and the less then 60% debarking for the weakest trees.

 

[UK_EF4]

 

[A Guy]

Wait someone's actually dug up that old paper? The problems that the method seems to have from what I have worked out, are that the markings are not regular, instead varying in distance from the presumed centre, and their continuity is hard to discern - it's hard to tell if two loops were generated by the same bit of the storm, when the method relies on on the loops being continuous regularly formed cycloids. I would note that the estimates Fujita produced for Palm Sunday are actually in line with estimates from the EF Scale.

A fellow called Zimmerman did a PhD thesis about a decade ago, and found from simulations that the marks are formed at areas of high corner flow (abrupt change from horizontal to vertical wind) which deposits material, and do not necessarily require or coincide with subvortices. Also found that the presence or absence of marks was determined as much by the amount of loose material available as by the tornado structure - the loops don't form without sufficient loose material, producing the appearance of a 'single vortex' ground marking. It was suggested the marks may be interpretable for windspeed but no work seems to have been done to that end since.

 

[joshoctober16]

i would realy want them to look at all offical F5/EF5 and any offical 183+mph rated tornadoes with a fair look.

as in some have notice, using the reason why bremen and villonia didn't get rated EF5 would downgrade 95+ % of all tornadoes

the annoying issues are

1:trees standing 100 yards away reason.
2: only one EF5 di , and not 2 of them , thus we cant not rate it EF5.
3:debris from other homes hit into this house and swept clean this home, thus we rated it weak EF2.

if you use these 3 things and put it to any tornadoes im pretty sure there would be almost no violent tornadoes at all.


note there are some stuff i should update on this, but take note on the right for the reason why they would not be rated EF5, parkersburg would be the only one to have a EF5 rating using all there weird post villonia reasons.

im also noticing a lot of past F5 don't even look EF5, or even EF4 by today's EF scale.

(edit: for some stupid reason each time i put 2: it sometimes changes it into a emoji...)

 

[andyhb]

Those of you heavily invested in this discussion will probably want to give this a read @buckeye05.

Comparison of Tornado Damage Characteristics to Low-Altitude WSR-88D Radar Observations and Implications for Tornado Intensity Estimation

Abstract Given the obvious difficulties in directly sampling tornadic wind fields, ongoing work continues to improve estimates of near-ground wind speeds in tornadoes. This study builds upon a recently proposed empirical relationship between radar-observed velocities in the lowest 150 m AGL and...

journals.ametsoc.org

Consistent with recent work, damage-estimated tornado wind speeds tend to be lower than radar-estimated near-surface wind speeds, especially for stronger tornadoes. Damage- and radar-estimated wind speed differences are not strongly related to the availability of damage indicators (as measured by HUD). While some relationship exists—particularly underestimates of peak wind speeds for strong–violent tornadoes in low HUD areas—the tendency of radar-based strong/violent tornado intensity estimates to be meaningfully higher than EF-scale-based damage estimates exists across the HUD spectrum. The legacy F-scale wind speed ranges may ultimately provide a better estimate of peak tornado wind speeds at 10–15 m AGL for strong–violent tornadoes and a better damage-based intensity rating for all tornadoes. These results are contextualized with regards to ongoing community efforts to improve tornado intensity estimation.

 

[andyhb]

 

[pohnpei]

Those of you heavily invested in this discussion will probably want to give this a read @buckeye05.

Comparison of Tornado Damage Characteristics to Low-Altitude WSR-88D Radar Observations and Implications for Tornado Intensity Estimation

Abstract Given the obvious difficulties in directly sampling tornadic wind fields, ongoing work continues to improve estimates of near-ground wind speeds in tornadoes. This study builds upon a recently proposed empirical relationship between radar-observed velocities in the lowest 150 m AGL and...

journals.ametsoc.org

Tornadoes
with V15m speeds in the EF0–EF1 range generally match well to the VEF, while V15m
speeds exceeding EF3 intensity are often much higher than VEF, often by two to three EFscale rating categories

only three of the 194 observations
in this study were given VEF values that represent the peak possible wind speed that could
be assigned to that DI, thus limiting the effects that the capping of the intensity that each
DI is able to estimate has on this analysis

Remarkable work. The magnitude of underestimation of wind speed inside intense and violent tornados by EF scale are astounding but expected.
And it's also amazing to me that how Fujita could got such good and near accurate understanding of tornados with almost no observation data at his time.

We acknowledge that thespace-
time conversion here assumes the tornado-
scale flow is approximately constant on the
spatiotemporal scale being observed. Similar
to other methods discussed in section 2a,
thesegust periods should yield a greater und-
erestimation of near-surface wind speeds rel-
ative to VEF ifthe EF-scale estimates of inte-
nsity are accurately capturing the near-
surface intensity of thetornadoes.

It should be noted that there's still a general underestimation of wind speed of tornados with this dataset due to the limitation of WSR88D radar.

 

[joshoctober16]

View attachment 24408View attachment 24409

man its so good to finally see what ive been trying to tell people, that EF3+ tornadoes tend to be more violent then people think they are, however im shock to see zero true over rated tornado event on this graph (as in over 2 EF rating too high, theres none in the gray colored in area)

 

[Casuarina Head]

The rating was based on scouring in a corn field which is a bit questionable to say the least. I agree with the F5 rating because it caused vehicle damage and debarking consistent with some of the highest-end tornadoes and swept away a few anchor-bolted homes, but then again pretty much all violent tornadoes outside of DGX and DMX’s survey areas would get a HE EF3 rating these days. Low end EF4 is about as strong as they come now.

Re: the homes, if I recall correctly, Dr. Fujita concluded that the peak structural damage was mid-to-high-end F4 at most, and occurred in Lily Cache and Crystal Lawns rather than Plainfield itself, which incurred F3 structural damage, per the isolines. Nevertheless, in his study of Plainfield he noted that ground scouring in the populated areas was notably less severe than it was in the rural area where a small F5 contour was assessed, just northwest of Plainfield. I was looking back at Plainfield and, while agreeing that damage to the corn probably cannot be used as a DI on its own, the fact that nonconventional DIs such as scouring, vehicular impacts, etc. were seemingly less in the populated areas does lend credence to the existence of F5 winds elsewhere. As assessed by Dr. Fujita the F5 damage was apparently very localised, along Steiner Rd between CR 126 and W 143rd St, and I believe that the debarking of the tree and the extreme vehicular damage, including the carrying of the 20-ton tractor-trailer nearly 1/2 mi, occurred in this area.

 

[Casuarina Head]

Lubbock apparently did some intense ground scouring, while debarking trees and low-lying shrubbery. An engineering-study concluded that the lofting of the tank etc. could not be taken as indicative of F5 winds, but Dr. Fujita apparently may have given more weight to other factors in assigning the F5 rating. Interestingly, the aforementioned study concluded that winds of 183-200 mph (equivalent to high-end EF4) would have been required to carry the 13-ton metal tank 3/4 mi. Also, the worst-hit areas—extending from the Guadalupe neighborhood to the southern edge of the airport—may not have been photographed in detail for the most part. So I think that Lubbock was at least capable of low-end EF5 damage, poor quality of construction notwithstanding.

Xenia has already been covered in the “Significant Tornadoes” thread and, like Brandenburg, Guin, and both Tanner tornadoes, definitely seems EF5-worthy. Hesston produced some notable ground scouring, debarking, and extreme damage to vehicles in rural areas, so it was probably EF5-capable as well. I think the contextual evidence may also support EF5 winds in Plainfield as well, albeit over a very small area. Re: Mayfield, I think that the scouring near Cayce, the damage to churches in Mayfield, and the contextual (non-structural) DIs near Bremen and Dawson Springs, taken together, are enough to support EF5 winds at certain spots. Even though the UK facility in Princeton was not properly constructed, the scouring and vegetative damage nearby was noteworthy.

 

[TH2002]

Lubbock apparently did some intense ground scouring, while debarking trees and low-lying shrubbery. An engineering-study concluded that the lofting of the tank etc. could not be taken as indicative of F5 winds, but Dr. Fujita apparently may have given more weight to other factors in assigning the F5 rating. Interestingly, the aforementioned study concluded that winds of 183-200 mph (equivalent to high-end EF4) would have been required to carry the 13-ton metal tank 3/4 mi. Also, the worst-hit areas—extending from the Guadalupe neighborhood to the southern edge of the airport—may not have been photographed in detail for the most part. So I think that Lubbock was at least capable of low-end EF5 damage, poor quality of construction notwithstanding.

I can't tell if there's any definitive ground scouring in the first aerial. However, This F5-damage example photo from the F-scale training manual is from Lubbock. Also willing to bet the home in the training manual photo is the same one visible in the background of the debarked tree photo. In any case, Lubbock deserved its F5 rating.

Xenia has already been covered in the “Significant Tornadoes” thread and, like Brandenburg, Guin, and both Tanner tornadoes, definitely seems EF5-worthy. Hesston produced some notable ground scouring, debarking, and extreme damage to vehicles in rural areas, so it was probably EF5-capable as well. I think the contextual evidence may also support EF5 winds in Plainfield as well, albeit over a very small area. Re: Mayfield, I think that the scouring near Cayce, the damage to churches in Mayfield, and the contextual (non-structural) DIs near Bremen and Dawson Springs, taken together, are enough to support EF5 winds at certain spots. Even though the UK facility in Princeton was not properly constructed, the scouring and vegetative damage nearby was noteworthy.

Ignoring the fact that it wouldn't be rated EF5 today (because nothing would), Xenia deserves a low-end F5 rating; the grass scouring and debris granulation in the Arrowhead area give credence to it. Hesston deserved its F5 rating and so did Goessel since both of them swept away anchor-bolted homes.

 

[NorthGaWeather]

Ignoring the fact that it wouldn't be rated EF5 today (because nothing would)

I don’t normally engage in EF scale debates because it’s pointless…especially when comparing F scale ratings; however, I think this is incorrect. I realize there have been some significant discrepancies between offices and even individuals within those offices that make this seem like reality, but it simply isn’t. EF-5 ratings are attainable, IMO, and will occur again. Based on everything I’ve seen regarding Xenia, any competent survey team would rate it an EF-5.

I will say, I’ve been on surveys where the team was very strict to the EF scale and favored lower bound estimates. I’ve also experienced others where a seasoned individual assigned ratings that favored high end wind speeds based off their experience. There is a lot of subjectivity at times.

 

[TH2002]

Based on everything I’ve seen regarding Xenia, any competent survey team would rate it an EF-5.

Doubt it. Good construction quality is absolutely necessary for an EF5 rating, and that wasn't present in Xenia. To be honest I'm not sure how I feel about that, but unless I'm misunderstanding something, that is how the EF scale works.

Comparing F scale ratings to EF scale ratings is pointless because the scales are de jure equivalent, but not de facto equivalent.