Severe Weather Threat 4/25-4/26, 2024 - (Thursday, Friday)

[CheeselandSkies]

Hmmmm...now they've revised the page title into simply "outbreak" and omitted April 25 from the period covered.

 

[DetectiveWX]

The close up reminds me of McConnell AFB after it went into multi-vortex mode which, ironically, happened 33 years to the day... (Yes, I'm 3 weeks late)

 

[tornado examiner]

So uhm….the elkhorn tornado now has two low end EF4 home di’s added to it’s D.A.T survey…with specific descriptions of the damage and one has the 167 mph rating while the other is a 170…

 

[Equus]

Definitely looks the part, would not be shocked to see that become an official bump from 165 to 170 on Storm Data

 

[tornado examiner]

 

[buckeye05]

Definitely looks the part, would not be shocked to see that become an official bump from 165 to 170 on Storm Data
View attachment 29433
View attachment 29434

I am honestly a bit surprised that THIS house is one that's being used as basis for a likely upgrade because of three reasons: the first one being that the subfloor stayed attached to the foundation, the second being that the DAT says nails were the main connection between the walls and foundation, and the third being the fact that another home in a more rural area closer to Bennington DID have its subfloor torn completely off. The difference is that the cars at the house near Bennington weren't thrown, and the cars at the EF4-rated home shown above WERE thrown. Is context the discerning factor here?

 

[buckeye05]

This is the one I was talking about. There are bolts, however after looking at this again months later, I see a total lack of any nails connecting the sill plates to the walls here. Not even a few bare-minimum straight nails. I'd say that plays in the role in the EF3 rating there.

 

[Sawmaster]

This is the one I was talking about. There are bolts, however after looking at this again months later, I see a total lack of any nails connecting the sill plates to the walls here. Not even a few bare-minimum straight nails. I'd say that plays in the role in the EF3 rating there.


The studs wouldn't attach here. This would have had a floor system sitting on it with joists, rim bands,and plywood on top. The wall plates would have sat on top of that, and the floor system would have probably been toe-nailed to these plates you see here. That is not a strong connection but is typical "drop sill" construction in most places. Often those toe-nails would have split out of the rim and floor joists and been left in this plate, which I'm seeing none of here so essentially mostly or only gravity was holding this floor system down. Very poor construction in this regard.

 

[Equus]

Realistically 4/26 had at least three violent tornadoes, we're just limited to dealing with how the application of the EF scale always seems to handle what's considered 160-170 level damage

 

[Tanner]

Realistically 4/26 had at least three violent tornadoes, we're just limited to dealing with how the application of the EF scale always seems to handle what's considered 160-170 level damage

Three? I can only think of two.

 

[TH2002]

This is the one I was talking about. There are bolts, however after looking at this again months later, I see a total lack of any nails connecting the sill plates to the walls here. Not even a few bare-minimum straight nails. I'd say that plays in the role in the EF3 rating there.

Poor construction aside, it appears that part of the poured concrete foundation failed which is rather impressive. Definitely nowhere near EF5 level winds here (the heap of intact walls and other large chunks of debris left nearby says a lot) but wouldn't be surprised if this home was indeed impacted by lower-end violent winds. Don't know if the foundation was properly reinforced, and I'm sure the fact that it was a walk-out basement wall likely played a part in its destruction.

 

[TH2002]

To illustrate my point better, here's a home from the 2002 La Plata tornado that failed in a very similar fashion to the Elkhorn home. Poured concrete basement wall blown down, debris left in a pile nearby. Do think the La Plata example is a bit more impressive though, since the basement wall was actually flipped and blown inward and the debris pile seems to lack any intact walls. Again, don't consider this F5 damage, but definitely a solid candidate for at least low-end F4.

Another angle of the Elkhorn home:

 

[Sawmaster]

Don't know if the foundation was properly reinforced, and I'm sure the fact that it was a walk-out basement wall likely played a part in its destruction.

I can't see any reinforcing. That's rather common in residential wall and stem wall construction. With wind pressure, even a moderate impact could crack off a piece of unreinforced concrete like snapping a hard cookie in two. Reinforcing prevents such breakage and reduces the chances of cracking.

 

[tornado examiner]

Its now officially rated ef4

 

[tornado examiner]

This is the one I was talking about. There are bolts, however after looking at this again months later, I see a total lack of any nails connecting the sill plates to the walls here. Not even a few bare-minimum straight nails. I'd say that plays in the role in the EF3 rating there.

This home was upped to EF4

 

[TH2002]

Its now officially rated ef4

Good call by NWS Omaha, and goes to show how thorough they were. Upgrade took a little over three months, but better late than never I suppose.

 

[Western_KS_Wx]

Good call by NWS Omaha, and goes to show how thorough they were. Upgrade took a little over three months, but better late than never I suppose.

I always felt the initial rating was questionable, considering the sheer number of homes completely leveled or swept clean. Glad to see them going back and reviewing the damage more thoroughly and making the right call in this case.

 

[CheeselandSkies]

Oh wow, I guess I completely missed the boat on which tornado from this outbreak was actually being considered for an EF4 upgrade. I was sure if any it would be Minden-Harlan. I realize visual appearance is not a determining factor in tornado ratings, but that thing was absolutely monstrous; at times resembling Rochelle and/or Keota.

Still, it seemed like a glaring error of omission that this outbreak did not, officially, contain a violent tornado. At least that has been rectified.

 

[tornado examiner]

I always felt the initial rating was questionable, considering the sheer number of homes completely leveled or swept clean. Glad to see them going back and reviewing the damage more thoroughly and making the right call in this case.

One of the homes rated EF4 now was…originally rated mid range EF2…

NWS Louisville Kentucky take notes.

 

[Shakespeare 2016]

To illustrate my point better, here's a home from the 2002 La Plata tornado that failed in a very similar fashion to the Elkhorn home. Poured concrete basement wall blown down, debris left in a pile nearby. Do think the La Plata example is a bit more impressive though, since the basement wall was actually flipped and blown inward and the debris pile seems to lack any intact walls. Again, don't consider this F5 damage, but definitely a solid candidate for at least low-end F4.

Another angle of the Elkhorn home:

Though there is a lack of contextual that home damage looks pretty impressive.