Enhanced Fujita Ratings Debate Thread

[Ozonelayer]

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Looks like it was one of these bad boys.

Assuming its empty, lets do the calculations.
Using some quick geolocating, the hill is an approxamite 15 degree angle. Now for the math. (Using bold cause its easier to see)

Train car dimensions:
Length L = 60.1 ft ≈ 18.31 m
Width W = 10.8 ft ≈ 3.29 m
Height H = 10.5 ft ≈ 3.20 m
Mass m = 63,600 lbs ≈ 28,850 kg
Position: 40 m up a 15° slope
Car shape: approximate cylinder (frontal area roughly circular when facing wind)


Step 1: Estimate Frontal Area
A ≈ H × W = 3.20 × 3.29 ≈ 10.53 m²


Step 2: Estimate Wind Force
F_wind = 0.5 × ρ × C_d × A × v²
ρ = 1.225 kg/m³, C_d ≈ 1.2, A = 10.53 m²
F_wind ≈ 0.5 × 1.225 × 1.2 × 10.53 × v² ≈ 7.74 v² [N]


Step 3: Determine Resistive Force (Static Friction + Grade)
Rolling resistance: F_rr = μ_rr × m × g × cosθ
μ_rr ≈ 0.002, g = 9.81 m/s², θ = 15°
F_rr ≈ 0.002 × 28,850 × 9.81 × cos15° ≈ 546.7 N


Grade resistance: F_grade = m × g × sinθ
F_grade ≈ 28,850 × 9.81 × sin15° ≈ 73,300 N


Total resistive force: F_resist = F_rr + F_grade ≈ 546.7 + 73,300 ≈ 73,850 N


Step 4: Solve for Wind Speed
Set F_wind = F_resist to just start moving:
7.74 v² = 73,850
v² ≈ 73,850 / 7.74 ≈ 9,542
v ≈ 97.7 m/s ≈ 219 mph ≈ 352 km/h

So unless I am wrong (I could very well be. I'm still learning how to calculate windspeed), It would mean the Train Car had to have been exposed to ~220 MPH winds at minimum

 

[buckeye05]

Assuming its empty, lets do the calculations.
Using some quick geolocating, the hill is an approxamite 15 degree angle. Now for the math. (Using bold cause its easier to see)

Train car dimensions:
Length L = 60.1 ft ≈ 18.31 m
Width W = 10.8 ft ≈ 3.29 m
Height H = 10.5 ft ≈ 3.20 m
Mass m = 63,600 lbs ≈ 28,850 kg
Position: 40 m up a 15° slope
Car shape: approximate cylinder (frontal area roughly circular when facing wind)


Step 1: Estimate Frontal Area
A ≈ H × W = 3.20 × 3.29 ≈ 10.53 m²


Step 2: Estimate Wind Force
F_wind = 0.5 × ρ × C_d × A × v²
ρ = 1.225 kg/m³, C_d ≈ 1.2, A = 10.53 m²
F_wind ≈ 0.5 × 1.225 × 1.2 × 10.53 × v² ≈ 7.74 v² [N]


Step 3: Determine Resistive Force (Static Friction + Grade)
Rolling resistance: F_rr = μ_rr × m × g × cosθ
μ_rr ≈ 0.002, g = 9.81 m/s², θ = 15°
F_rr ≈ 0.002 × 28,850 × 9.81 × cos15° ≈ 546.7 N


Grade resistance: F_grade = m × g × sinθ
F_grade ≈ 28,850 × 9.81 × sin15° ≈ 73,300 N


Total resistive force: F_resist = F_rr + F_grade ≈ 546.7 + 73,300 ≈ 73,850 N


Step 4: Solve for Wind Speed
Set F_wind = F_resist to just start moving:
7.74 v² = 73,850
v² ≈ 73,850 / 7.74 ≈ 9,542
v ≈ 97.7 m/s ≈ 219 mph ≈ 352 km/h

So unless I am wrong (I could very well be. I'm still learning how to calculate windspeed), It would mean the Train Car had to have been exposed to ~220 MPH winds at minimum

Incredible considering that Barnsley wasn’t even where the most intense damage occurred, in fact, the damage there was rated EF3. Just imagine what the windspeed was in Bremen, or downtown Mayfield, or Cambridge Shores.

 

[Grand Poo Bah]

Tim Marshall will be on Fox Weather to discuss the Enderlin rating in the next 15-20 minutes.

Livestream of Fox Weather for anyone interested

 

[sripey]

This may blow the lid off of the current set of wind speed estimates. I think we’re all starting to realize that Fujita had it right the first time around, and I hope the experts can put their pride aside and reach the same conclusion.

While I agree the research paper really opens things up, I think some are overlooking a potentially significant caveat the papers authors included. I encourage everyone to read the paper in full.

"However, there are some limitations to this study that prevent this argument from being fully realized. An example of this is the potential overestimation in wind speed due to the importance of the initialization of debris lofting in tornadic wind fields (Huo et al. 2023). In this study, it was observed that while the presence of an updraft flow does not ensure
that the debris will become airborne, the debris initialization correlated well with the vertical velocity component and resulted in an increased likelihood of lofting at the location of the core radius of the vortex (r 5 rm). Notably, the current lift coefficients for vehicles used in this study are based on a
purely horizontal wind speed, which generates a lift due to the difference in pressure created on the roof of the vehicle to the undercarriage below the vehicle as the surrounding air moves through it (Heisler 2004). Therefore, there is a current disconnect in the lift coefficients used for the vehicles in this study and the likely physics causing the initiation of lofting for these objects in a tornadic wind field. It seems likely that more realistic coefficients may decrease the lofting windspeed. However, there are no data available for lift coefficients of these objects in a tornadic wind field, which should
be a topic of future research."

 

[jiharris0220]

Is this what people felt like during the Renaissance?

Everyone knew that it obviously took 200+mph winds to loft fully loaded train carts several dozen meters, but I never in my wildest dreams did I even consider the NWS would actually go through with it.

Lyzes’ paper along with the Northern Tornado Project definitely pushed the rating community over (up to this point) a seemingly un-scalable wall.

I really thought ef5s were a thing of the past now, but with this, a hopefully new can of worms have been opened and tornadoes will actually be properly rated now, along with past tornadoes being reanalyzed.

 

[Lake Martin EF4]

On this date, the day we confirm the end of the EF5 drought, I also want to make a detour and talk about some hurricane C5 droughts:

• The EPac C5 Drought (1973-1994) - Started with Ava 1973, ended with Emilia 1994. Longest period between EF5s in any basin in history. That said, satellite evidence suggests that there were several C5s in the period (the mid 80s in particular appears to have been positively overflowing with them, including one specific storm (Sandra 1985) which is officially a C3 but which is unanimously considered a C5 by most amateur reanalyzers - some of whom put it at 185 mph!)
• The Atlantic C5 Drought (2007-2016) - Started with Felix 2007, ended with Matthew 2016. I recall this being compared to the EF5 drought a bit. Like the EPac drought, several C5 candidates (Gustav, Igor, Joaquin) exist in the drought timespan....and I also think Matthew will be downgraded if it ever gets a reanalysis, so it may officially become 10 years. After this, almost every year (and indeed every year IMO) since has included at least one C5.

 

[buckeye05]

Tim is dodging those hard questions lol. Not liking how he’s handling this.

 

[sripey]

Tim is dodging those hard questions lol.

He sure is.

 

[tornado examiner]

Tim is dodging those hard questions lol.

What do you mean?

 

[TH2002]

Tim is dodging those hard lol. Not liking how he’s handling this.

Definitely some vague answers there... especially that last tweet he responded to. Still, gotta give him credit for finally acknowledging that non-DI's can be assigned EF ratings under the right circumstances... and saying that forensic engineering to estimate wind speeds will be an important part of damage surveying going forward.

 

[buckeye05]

I think what people want to know is if this can be applied retroactively. Vilonia, Tuscaloosa, and Mayfield all come to mind.

 

[jiharris0220]

Tim is dodging those hard questions lol. Not liking how he’s handling this.

I don’t blame him. It’s really the fact that with this tornado’s rating, and comparing it to other tornadoes in the same year and the past 12; it’s become pretty clear to even weather novices that this ef5 drought didn’t “happen by chance”.

 

[Shakespeare 2016]

Definitely some vague answers there... especially that last tweet he responded to. Still, gotta give him credit for finally acknowledging that non-DI's can be assigned EF ratings under the right circumstances... and saying that forensic engineering to estimate wind speeds will be an important part of damage surveying going forward.

Well, it is about time he said that. Why couldn't this have been addressed like 10 to 15 years ago?

 

[tornadowatch211]

This thing might’ve bent railroad track and cracked concrete. Not joking

 

[Lake Martin EF4]

especially that last tweet he responded to

What was the tweet and response?

 

[ColdFront]

That producer on Fox Weather has to be one of us lol. He had Ari book Convective Chronicles one night, and now he’s throwing up those pointed tweets to Marshall about the EF scale.

@buckeye05 he was absolutely dodging those questions. A lot of “non answers” in there.

 

[tornado examiner]

This thing might’ve bent railroad track and cracked concrete. Not joking
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Chapman incident

 

[buckeye05]

What was the tweet and response?

It was regarding missed EF5s and the human error-induced nature of the EF5 drought, and whether this establishes a way to go back and upgrade them.

He called critics “backseat drivers” and said the NWS is “in the know” and knows what they’re doing, and didn’t say whether further retroactive upgrades are possible or not.

 

[Grand Poo Bah]

What was the tweet and response?

The reporter pressed him about going back and rerating tornadoes with 3 separate tweets at different points in the interview. The tweets were outlining the exact stuff we've been talking about today. He basically deflected the first two by saying the EF scale is getting the "upgrade" so tornadoes can be rated correctly going forward. On the third tweet he finally caved and answered and said the weather community is full of "backseat drivers" and they should leave surveying up to the professionals. I was more amused by it than disappointed because I really wasn't expecting him to just straight up say "yeah we sure have F'd up a lot!" live on air lmao. It's frustrating that he doesn't seem to be open to re-rating at all though.

 

[sripey]

That producer on Fox Weather has to be one of us lol. He had Ari book Convective Chronicles one night, and now he’s throwing up those pointed tweets to Marshall about the EF scale.

@buckeye05 he was absolutely dodging those questions. A lot of “non answers” in there.

Lol. Yeah I was pleasantly surprised to see those questions put to Marshall. Personally I don't have a big problem with Marshall other than he's a bit smug, but he sounded like a politician when answering those questions.