Sheridan County, MT deadly tornado only rated EF-3?

[Lanny Dean]

Thought this would be a decent discussion and maybe even get some of those who have had issues with the current EF scale.

Was doing some research this evening and found that the NWS-Glasgow has finally given the Sheridan MT tornado an EF-3 rating. After looking at damage pictures and video of the tornado it seems very clear to me that this event was not rated correctly. Link here:
http://www.wrh.noaa.gov/ggw/SheridanTornSumm.pdf

I suspect that this is due to that particular CWA/staff not experiencing these type of events. As you can see in the pictures, the house and all outbuildings were destroyed....more importantly, the house was not just destroyed, it is totally gone! Not even a foundation left.
Cars from the Smith ranch were found up to 1/4 mile away and large debris has been found 2-3 miles away from the ranch house.
IMO this deadly tornado clearly has been underated due to inexperience. Taking a look at the damage indicators for current EF scale, this should have been rated at least a strong EF-4 tornado. Cars became missles and were lofted long distance (over 3,000ft) or rolled...the smith ranch house was totally destroyed...no walls or structure left standing with very little if any real debris left near the homestead.

IMHO, if this had been in the OKC, ICT or "normal" weather markets, this would have received a higher rating. To me, this just goes to show and prove that the Enhanced scale is worthless if all damage indicators and degree of damage are not followed. I know we have beat this horse to death but the old F scale was changed due in part becuase it was subjectional....with this latest rating it should be very clear that the Enhanced scale holds the very same problems it was invinted to correct.

IMO, this event should be rated again by those who have experienced this type of devastation and destruction.

I might add that I am not trying to disrespect anyone especially those that took part in the survey...just curious to know if this is a possible reason for such a low rating?

Thoughts???

 

[Wes Carter]

I still find the application of the Enhanced Fujita scale to be a bit confusing. Looking at the report, I agree. It looks worse than EF-3 damage. The only thing that I would have any qualm about is referencing appendix a of the Enhanced Fujita Scale paper, they refer to DOD 10 as total destruction of a single or double family residence of 1000 to 5000 square feet, with assumptions being made about the quality of construction. And since the greatest destruction determines the rating, it looks like at least on the Smith ranch this would qualify as at least EF-4 damage if the house was determined to have met the quality of construction requirements.

The first house in the photos appeared to be a 2 story wood frame house of the type built 50 or more years ago. It was moved off of it's foundation, but appeared to be all together. I'm curious if the Smith ranch home was of this type or newer construction. I'm taking a guess here, but I'll bet these houses were not attached to the foundations very well. I'm not familiar with construction practices in Montana, in the area I'm from many older homes were not even attached to the foundations, they are just sitting on them. They were made often framed with hardwood lumber, were heavy as crap, and very strong. But still, they provide a lot of horizontal surface area subject to wind loading.

Either way, it looks every bit as impressive as the damage from the Murfreesboro, TN EF-4 from April 10 of last year. I know you've seen a lot more damage than I have over the years, so I give your opinion a lot of weight. But I do wonder if the quality of construction weighed heavily in this one.

 

[Shane Adams]

Dollars to dimes the issue is the construction of the house. Mulvane leveled a two-story ranch house, leaving nothing but an exposed basement. It also tossed a vehicle (with motor intact) 275 yards. But they went F3 because a light pole in the yard wasn't damaged and a tree in the yard wasn't debarked.

My guess is the F3 rating is due to some technicality about how the farmhouse was constructed.

 

[Scott Weberpal]

As you can see in the pictures, the house and all outbuildings were destroyed....more importantly, the house was not just destroyed, it is totally gone! Not even a foundation left.

The upper bound of wind speed for completely destroying farm outbuildings is 130mph. Growing up on a farm, we have had 80mph straight line winds almost completely destroy outbuildings, especially pole sheds that remain partially exposed. As far as the house is concerned, is there any indication as to how well constructed it was? Viewing the aerial damage photo, it doesn't look like we have a very good view of the house foundation as the house did have a basement but we can not see it in the photo due to it being filled with/block by debris from both the house and trailer. I also agree with Wes that there is a high likelihood that the house was not anchored to the foundation. If that is the case, EF-3 type winds would have no problem pushing the house off the foundation and obliterating it. Given much of the debris from the house is 30-40 feet from where it originally was, that seems like a likely conclusion.

From NWS Glasgow: The upper middle of the photo shows a brown spot that held a single wide trailer, and the white in the photo shows the foundation of the two story house. The majority of the home debris was in the pile in the center of the photograph with the yellow vehicle in it.

This is what I take from that. Unfortunately they don't have any good ground photographs of the house and focused a lot on the vehicles...

If what I am seeing is correct, then the trailer was only moved a couple dozen feet at best and remained partially intact. Because the trailer was moved on top of or in front of the house foundation (at least from this vantage point) it is impossible to tell how much debris from the house and or if the foundation still remains.

Cars from the Smith ranch were found up to 1/4 mile away and large debris has been found 2-3 miles away from the ranch house.

ONE truck was found 1/4 mile away, and there is no mention in the report that any debris was found 2-3 miles away. Was the truck thrown 1/4 mile, or was it rolled 1/4 mile? It also appears that virtually every other vehicle remained very near where it originally was.

IMO this deadly tornado clearly has been underated due to inexperience. Taking a look at the damage indicators for current EF scale, this should have been rated at least a strong EF-4 tornado.

I could understand high-end EF3 or low-end EF-4, but not a strong EF4

Cars became missles and were lofted long distance (over 3,000ft)or rolled...

Actually, 1/4 mile is closer to 1,300ft.

the smith ranch house was totally destroyed...no walls or structure left standing with very little if any real debris left near the homestead.

It looks like most of the debris from the house remained within a few dozen feet of the house with much debris remaining within the foundation. Even a good part of the trailer was only blown a few dozen feet. This also goes back to the house possibly being un-anchored.

Of course, this is all based on what I am seeing and my un-trained assessment of what the aerial photographs show. I may be correct, I may be completely wrong - I just with Glasgow did a better job taking ground-level photographs to get a better understanding of what the damage looked like and to be more precised with locating various buildings in the aerial photograph. I believe they are spot on with their damage assessment, though, it potentially could have been rated low-end EF-4. Again, without a closer view of the home, it is impossible to say if there were any interior walls left standing under all that debris or if all that debris is piled in the basement.

 

[Andy Jackson]

I'd say they made a conservative estimate possibly because of the sparsely populated area the tornado affected.

 

[Chad Berryhill]

I'm trying to start a fight or disrespect, but what about the bridge ? There is a little more than just a couple of nails holding that bridge together. I understand the wind tunnel effect, but wow. That's going to take a pretty decent wind to tear it apart.

I'm not trying to steer this discussion away from the house. You all have interesting points and thoughts about the assessment. I'm sure some ratings are not easy while others are blatantly obvious.

We will never get a real good "eye" on the damage, unless we all head up there now, and I would imagine some of that mess has been cleaned up already.

I really hate it when people are hurt or killed. My condolences go out to the family.