Significant Tornado Events

[TH2002]

Incidentally, another example of a well-deserving F5 that probably wouldn't be an EF5 today - the sill plates were anchor bolted, but the foundation walls were CMU.

(Although there were also a few slab homes swept away, so I suppose there's a chance it might earn an EF5 today. But probably not with the way things are going.)

I think in cases like that where the CMU foundation shows little to no evidence of having failed underneath the home, I see no good reason to not go with an F5/EF5 rating. Unlike obvious cases like Ruth/Arab where the foundation clearly did fail underneath the home, you don't see that here except in a few spots. The basement walls are mostly underground and mostly intact.

So with that in mind, should an EF5 rating still be mitigated?

 

[buckeye05]

What’s interesting is that if a CMU foundation remains undamaged after a tornado, that is sometimes taken into account for a violent rating. There’s a video presentation by a NWS surveyor on YouTube of the summary and rating decisions for the Dalton, MN EF4. At the home that was the basis for the rating, it was noted that none of the concrete blocks were pulled or shifted from the foundation, which was determined to be evidence of good construction, and subsequently an EF4 rating.

 

[locomusic01]

I think in cases like that where the CMU foundation shows little to no evidence of having failed underneath the home, I see no good reason to not go with an F5/EF5 rating. Unlike obvious cases like Ruth/Arab where the foundation clearly did fail underneath the home, you don't see that here except in a few spots. The basement walls are mostly underground and mostly intact.

So with that in mind, should an EF5 rating still be mitigated?

What’s interesting is that if a CMU foundation remains undamaged after a tornado, that is sometimes taken into account for a violent rating. There’s a video presentation by a NWS surveyor on YouTube of the summary and rating decisions for the Dalton, MN EF4. At the home that was the basis for the rating, it was noted that none of the concrete blocks were pulled or shifted from the foundation, which was determined to be evidence of good construction, and subsequently an EF4 rating.

Yeah, that's the whole problem. There's really no reason construction like this should be immediately disqualifying for EF5, and I'm not aware of anything in the EF-scale itself that precludes it, but would anyone be confident it would actually be rated as such? The contextual evidence in this area was clearly supportive (significant wind rowing and debris granulation, some fairly high-end vegetation damage, etc.) but apparently that's not a factor for many surveyors now.

Anyway, I guess that's a tangent/rant for another thread lol. While I'm on the subject of this specific area though, there's one thing I'm still dying to get some clarity on. At a house just across the street, a couple of different newspaper articles reported that pieces of the foundation were dislodged/torn away (variously reported as "part of the slab was broken/pulled up," "part of the foundation was carried away," etc.) I haven't been able to get in touch with the couple who owned the place yet, but I talked to a couple neighbors and family members and they all recalled the same general story.

I'm obviously very skeptical - as we all know, these kinds of reports aren't uncommon in violent tornadoes, and they almost always end up being misinterpretations - but something clearly happened and I'd love to understand what it was. Unfortunately, there's not much to go on unless I can find some better pictures.

 

[TH2002]

What’s interesting is that if a CMU foundation remains undamaged after a tornado, that is sometimes taken into account for a violent rating. There’s a video presentation by a NWS surveyor on YouTube of the summary and rating decisions for the Dalton, MN EF4. At the home that was the basis for the rating, it was noted that none of the concrete blocks were pulled or shifted from the foundation, which was determined to be evidence of good construction, and subsequently an EF4 rating.

The foundation did actually fail under part of the home, albeit the failure was not extremely significant.


But it is still interesting to note that on a part of the foundation that remained intact, at least one anchor bolt was bent at a 90 degree angle:

 

[TH2002]

i think the biggest offender is when they downgraded a home in oklahoma to ef4 because, yes, ITS BOLTS WERE SLIGHTLY TOO SMALL.....where is that kind of stuff on the ef-scale documents???? everything else around the home screams EF-5 intensity. yet simply cause the bolts were like, a milimeter below normal size the entire house cant be rated EF-5...thus the tornado wasnt rated EF-5.....

like how nitpicky do you gotta be to do that??????

Which tornado are you talking about? Goldsby?

 

[andyhb]

A picture of the aftermath of the Goliad TX tornado on May 18th, 1902. Complete devastation here.

The video (linked below) also shows a steel girder from a bridge that was thrown a mile and deeply embedded in the ground in someone's backyard, where it still stands today: https://www.kiiitv.com/article/news...ial-report-goliads-1902-tornado/503-547419164

 

[andyhb]

Should note that video has been posted before, but the part about the steel girder wasn't mentioned.

 

[tornado examiner]

Which tornado are you talking about? Goldsby?

one of the ef4's of may 24 2011 yes cant remember exactly which one it was tho

 

[MNTornadoGuy]

one of the ef4's of may 24 2011 yes cant remember exactly which one it was tho

One of the Chickasha had some homes that didn’t get EF5 due to some of the anchor bolts missing washers. I think you might be thinking about that.

 

[Juliett Bravo Kilo]

One of the Chickasha had some homes that didn’t get EF5 due to some of the anchor bolts missing washers. I think you might be thinking about that.

Didn't something similar happen with Goldsby?

 

[buckeye05]

Didn't something similar happen with Goldsby?

Chickasha. This was one of the reasons they kept Rochelle/Fairdale at high-end EF4 too from what I understand. I mentioned in another thread though that I really question the validity of this, as I find it highly unlikely that construction workers framing a house would randomly skip the installation of washers on some bolts, yet install them on others at the same residence. Over the years, I've come to suspect that many of these "missing washers" cases are actually a result of some the bolts being stripped as the sill plates are ripped off.

I think this can be concluded as a construction error only in cases when every bolt is missing washers.

 

[MNTornadoGuy]

Footage of the 2008 Clinton AR tornado. Horizontal vortices are visible near the end of the 1st video.

 

[eric11]

Have some newly discovered damage photos from the 2014 Vilonia AR "EF4". I'm changing my mind as this tornado might not have been an EF5 candidate, instead, it could be the most violent tornado in AR history and one of the most violent tornado we've seen in decades.
Some Jarrell-esque in downtown Vilonia, debris and dismembered vehicle pieces piled against debarked trees, ground was heavily scoured and became muddy.

Extreme debris granulation near a small lake before tornado entering downtown Vilonia, there're at least 5 cars mangled beyond recognition and been thrown into the lake.All these pieces was cut into no bigger than hand size, similar to what we've seen in Pakersburg.

Cars near the lake.


A concrete(?) safety house was almost torn down, you can see the hard brick and concrete pieces around the safety house

 

[CheeselandSkies]

Goodness, the more I learn about Vilonia, the more egregious its underrating becomes. You're right, that is Parkersburg/El Reno '11-level debris granulation/vehicle mangling.

 

[eric11]

A local car dealarship in Vilonia took a direct hit. Dozens of cars were thrown long distance and mangled beyond recognition.At least a dozen car was found piling up in a ditch, others were caked in mud and thrown into the woods behind the car delarship, every car was literally mangled beyond recognition.This level of damage was extremely similar to the "car cemetery"near Moore Medical Center.


Shifting to east, the tornado did significant scouring to the field as little debris could be found, some cars from the car dealership flew hundreds of yards and landed right here, this whole place was devastated as if it was blown up by an atomic bomb.

 

[eric11]

If scouring asphalt is regarded as a non-official damage indicator when rating an EF5. Vilonia definitely warrants it

Extreme debarking was so common that literally every tree, regardless of softwood or hardwood suffered severe to complete debarking in the hardest hit area.


Extreme ground scouring.

 

[CheeselandSkies]

Credit goes to @andyhb but it must be said again...

 

[TH2002]

I have never seen such an unbelievably half-assed survey in my life.

Cemetery St:


The amount of DI's on that street:

 

[TH2002]

This is also EF4 damage according to John Robinson.

 

[eric11]

Other photos of damage from Alonsa. The tornado looks a lot like Katie 2016.

The tornado also dismembered cars, some axles and tires near a county road

and....what's this? ground digging or some impact marks from heavy object?

Semis thrown into the Manitoba Lake