Significant Tornado Events

[ARCC]

Interesting seeing another example of a storm shelter being compromised by a violent tornado besides Hackleburg and Vilonia. Maybe it isn’t as super rare as many think.

If most of the older ones are like mine, I’m sure most EF5s are capable of taking the roof off.

 

[speedbump305]

You said the same thing about Washington, IL. You can’t just say “I think there was scouring/debarking, but I have zero photographic proof or eyewitness accounts to support this.” That’s not making an educated inference, that’s just guessing with zero basis.

True, tbh el reno was still massively overrated, i have an image of some tree damage from El Reno that i’ll post

 

[speedbump305]

This was the only tree damage i have found for the El Reno 2013 Tornado. And btw this was from Tim Marshall’s survey

 

[buckeye05]

Actually now that I think of it, didn’t the Cordova, AL EF4 from 04/27/11 destroy an old underground concrete shelter as well? I seem to remember that people were in it when it happened too.

 

[Marshal79344]

Actually now that I think of it, didn’t the Cordova, AL EF4 from 04/27/11 destroy an old underground concrete shelter as well? I seem to remember that people were in it when it happened too.

Unsure, but I found it very interesting at how the core of that tornado was constantly reorganizing itself. It would widen out and produce a large swath of significant tree damage in places, and randomly contract into a very small core that produced ground scouring. I have a feeling it may have been an EF5 candidate when it was in rural areas south of Berry, before reaching Cordova.

 

[buckeye05]

Unsure, but I found it very interesting at how the core of that tornado was constantly reorganizing itself. It would widen out and produce a large swath of significant tree damage in places, and randomly contract into a very small core that produced ground scouring. I have a feeling it may have been an EF5 candidate when it was in rural areas south of Berry, before reaching Cordova.

Cordova was indeed very violent. I'd agree that it was capable of producing EF5 damage, and the trench digging that it produced could arguably be considered EF5 damage as is, based on the precedent set by the Philadelphia, MS EF5. In addition, the fact that it threw a utility trailer a full mile, which was lofted so high into the air that it left a 2.5 foot deep impact crater when it fell back to the ground, really impresses me. Also, a DAT check confirms that the Cordova tornado caused an underground storm shelter to collapse in the southern part of Cullman County near the small community of Arkadelphia. No photos of this are currently available though unfortunately.

 

[locomusic01]

Interesting seeing another example of a storm shelter being compromised by a violent tornado besides Hackleburg and Vilonia. Maybe it isn’t as super rare as many think.

It isn't - the same thing happened on at least one property in Bridge Creek, and I've come across similar examples in a few other tornadoes - but I think it's important to specify what kinds of structures we're actually talking about. In all the examples I'm aware of, the "storm shelters" in question were actually what older folks used to call storm caves/houses - basically just makeshift concrete shelters that aren't necessarily in great condition anyway. The doors are often pretty useless and the anchoring of the roof slab is usually, well.. not ideal.

Damaging a shelter like that is still an impressive feat and likely indicative of a very intense tornado, but it's entirely different from damaging a dedicated shelter that was properly built (or precast) to ICC/FEMA codes. Anything's possible I suppose, but it's pretty hard to imagine that happening.

 

[Marshal79344]

One interesting thing to note about the May 20, 2013, Moore, Oklahoma EF5 Tornado is what the radar picked up during tornadogenesis. The parent supercell was the only one to develop with a clear inflow notch, another cell to the south tried but was obscured. Despite this, the Moore Supercell had developed a hook echo and exhibited rather lower-end rotation for about 15 minutes prior to the tornado formation. The environment below certainly suggests the potential for tornadoes, but the lack of wind shear and kinematics doesn't exactly yell "VIOLENT TORNADO"

Observed Sounding from OKC at 18z (The tornado touched down at 19:56z)



However, an area of weak precipitation was seen moving towards the inflow notch of the tornadic supercell at around 1955z, and coincided with tornadogenesis.

1952z. No tornado is on the ground, but a rotating wall cloud was seen on radar. Notice the convection approaching the inflow notch from the south.



1956z. The tornado has touched down. Notice how the supercell is beginning to absorb the convection.



2000z, the tornado is on the ground, and is producing high-end EF4 damage to homes along Stanton Lane, just north of Newcastle. As the supercell began to suck in the convection, it appears to have given it a "boost" of some sort. The velocity signature has intensified exceptionally.



The convection appeared to have had a major effect on the parent supercell, likely due to the margnial kinematics. As soon as the convection had been absorbed, the supercell and tornado began to deviate further east of the original track.

 

[Juliett Bravo Kilo]

It isn't - the same thing happened on at least one property in Bridge Creek, and I've come across similar examples in a few other tornadoes - but I think it's important to specify what kinds of structures we're actually talking about. In all the examples I'm aware of, the "storm shelters" in question were actually what older folks used to call storm caves/houses - basically just makeshift concrete shelters that aren't necessarily in great condition anyway. The doors are often pretty useless and the anchoring of the roof slab is usually, well.. not ideal.

Damaging a shelter like that is still an impressive feat and likely indicative of a very intense tornado, but it's entirely different from damaging a dedicated shelter that was properly built (or precast) to ICC/FEMA codes. Anything's possible I suppose, but it's pretty hard to imagine that happening.

This reminds me of a previous post I made on a similar topic. It involves Chickasha and was extremely impressive, a concrete dome-type house that was specifically built to be tornado resistant and still severely damaged. Not exactly a "shelter" in the traditional sense but you get the idea.

Significant Tornado Events

He more or less said Chickasha was an EF5 too towards the end, yes. Around 1 hour and 29 minutes in for those who want to skip to it.

talkweather.com

 

[locomusic01]

This reminds me of a previous post I made on a similar topic. It involves Chickasha and was extremely impressive, a concrete dome-type house that was specifically built to be tornado resistant and still severely damaged. Not exactly a "shelter" in the traditional sense but you get the idea.

Significant Tornado Events

He more or less said Chickasha was an EF5 too towards the end, yes. Around 1 hour and 29 minutes in for those who want to skip to it.

talkweather.com

Yeah, the damage done to that monolithic dome was pretty striking.

 

[CheeselandSkies]

One interesting thing to note about the May 20, 2013, Moore, Oklahoma EF5 Tornado is what the radar picked up during tornadogenesis. The parent supercell was the only one to develop with a clear inflow notch, another cell to the south tried but was obscured. Despite this, the Moore Supercell had developed a hook echo and exhibited rather lower-end rotation for about 15 minutes prior to the tornado formation. The environment below certainly suggests the potential for tornadoes, but the lack of wind shear and kinematics doesn't exactly yell "VIOLENT TORNADO"

Observed Sounding from OKC at 18z (The tornado touched down at 19:56z)

View attachment 8993

However, an area of weak precipitation was seen moving towards the inflow notch of the tornadic supercell at around 1955z, and coincided with tornadogenesis.

1952z. No tornado is on the ground, but a rotating wall cloud was seen on radar. Notice the convection approaching the inflow notch from the south.

View attachment 8994

1956z. The tornado has touched down. Notice how the supercell is beginning to absorb the convection.

View attachment 8995

2000z, the tornado is on the ground, and is producing high-end EF4 damage to homes along Stanton Lane, just north of Newcastle. As the supercell began to suck in the convection, it appears to have given it a "boost" of some sort. The velocity signature has intensified exceptionally.

View attachment 8996

The convection appeared to have had a major effect on the parent supercell, likely due to the margnial kinematics. As soon as the convection had been absorbed, the supercell and tornado began to deviate further east of the original track.

View attachment 8997

The Knupp/Coleman et al. article on 4/27/11 mentions a similar phenomenon, and terms the weak radar echoes that were observed being drawn into supercells coinciding with or just prior to tornadogenesis as "reflectivity segments."

I noticed one of these myself in real time on my Radarscope while chasing on May 20, 2019. I observed it approaching the supercell southwest of Mangum, and correctly assumed the storm was about to become tornadic. Unfortunately, I mis-timed my intercept (given the expected environmental conditions on that much-vaunted high risk day, I anticipated tornadogenesis to occur very quickly, and long-lived tornadoes that would remain on the ground for many tens of miles, as the parameters that day were being compared to 4/27/11 but in the Plains) and by the time it produced, the updraft base was past my viewing location and I was unable to catch up due in large part to the extreme amount of chaser traffic around that storm.

My location is the blue crosshair, the linear east-west band of reflectivity was moving quickly north and collided with the supercell's inflow/updraft region shortly before tornadogenesis.

 

[Brice Wood]

The flint 1953 tornado just came into my mind.
An F5 hit the north side of flint and the northern suburbs of Beecher killing 116 people when everything was all said and done, it is the deadliest tornado in Michigan’s history and it’s the 10th deadliest tornado in the U.S.

Here’s one photo I found on wiki on the damage this thing caused

 

[TH2002]

Cordova was indeed very violent. I'd agree that it was capable of producing EF5 damage, and the trench digging that it produced could arguably be considered EF5 damage as is, based on the precedent set by the Philadelphia, MS EF5. In addition, the fact that it threw a utility trailer a full mile, which was lofted so high into the air that it left a 2.5 foot deep impact crater when it fell back to the ground, really impresses me. Also, a DAT check confirms that the Cordova tornado caused an underground storm shelter to collapse in the southern part of Cullman County near the small community of Arkadelphia. No photos of this are currently available though unfortunately.

Did the people in the storm shelter survive or was the shelter unoccupied?

 

[CheeselandSkies]

Some of the radar signatures of Cordova (if indeed it was the same tornado that started near Reform in Pickens County) were extremely impressive when it was in northern Tuscaloosa/far southeastern Fayette Counties, suggesting that at that point it was capable of far greater damage than its official 170 MPH/low-end EF4. In fact, if I recall correctly the only instances of official EF4 damage took place past Cordova, after the tornado had stopped receiving much attention from the TV coverage due to all eyes being on Tuscaloosa-Birmingham.

 

[buckeye05]

Did the people in the storm shelter survive or was the shelter unoccupied?

Nobody died in it, but based on my memory (so don’t quote me on this) there were some injuries that took place in the storm shelter.

 

[ARCC]

It isn't - the same thing happened on at least one property in Bridge Creek, and I've come across similar examples in a few other tornadoes - but I think it's important to specify what kinds of structures we're actually talking about. In all the examples I'm aware of, the "storm shelters" in question were actually what older folks used to call storm caves/houses - basically just makeshift concrete shelters that aren't necessarily in great condition anyway. The doors are often pretty useless and the anchoring of the roof slab is usually, well.. not ideal.

Damaging a shelter like that is still an impressive feat and likely indicative of a very intense tornado, but it's entirely different from damaging a dedicated shelter that was properly built (or precast) to ICC/FEMA codes. Anything's possible I suppose, but it's pretty hard to imagine that happening.

That is exactly how I feel about my “root cellar/storm shelter”. Essentially half buried CMU blocks with a probable un-anchored concrete top. Now I have removed the old door and replaced it with an anchored frame, but until I get a good layer of dirt across the top, I can easily see a high end tornado lifting the roof. Now it’s a thousand times safer than my house at the moment and the chance of getting hit by a very strong EF4-EF5 is about zero, so I’ll take my chances. However knowing my road network, I can drive away from a supercell obviously bringing that type of tornado to bear.

 

[speedbump305]

I’d love to get a radar loop of the Philadelphia and Smithville tornadoes

 

[TH2002]

Very rare video of a "previously un-documented" tornado near Nolensville, Tennessee, part of the 1974 Super Outbreak.

I have no idea if this tornado has ever been officially rated, or of the nature of the damage the tornado may have caused.

 

[CheeselandSkies]

Very rare video of a "previously un-documented" tornado near Nolensville, Tennessee, part of the 1974 Super Outbreak.

I have no idea if this tornado has ever been officially rated, or of the nature of the damage the tornado may have caused.

I'm curious what the original medium was, 8mm or Super 8 film? I ask because I had difficulty discerning negative dust spots and flicker typical of film, but home VHS didn't exist in 1974. The only things I see that support this was shot on film are some frame jitter on the left side at 0:08, and the rapid cuts typical of home shooting on the medium (video tape tended to be rolled more continuously).

That said, the source is NWS Hunstville, so I would hope they'd have done their due diligence on authenticating the footage. If accurate, this supports my suspicion about the 1974 Super Outbreak that a lot of tornadoes went uncounted, and the event was probably not as far behind the 2011 outbreak in terms of raw tornado count as the official numbers would suggest.

 

[CheeselandSkies]

I'm going to go through the Wikipedia tornado list to see if NWS Huntsville's phrasing of "previously undocumented" refers solely to visual documentation, or whether the tornado was totally unknown prior to discovery of this footage and thus not part of the official count.

Right off the bat, something is off about the second tornado of the day. It's described as "brief touchdown in an open field" at 13:30 UTC yet rated F2???

List of tornadoes in the 1974 Super Outbreak - Wikipedia

en.wikipedia.org

Update: There's an F2/possible F3 with a 4.7 mile path listed in the southeast Nashville area of Davidson County, TN at 2218 UTC (5:18 PM CDT). That was probably it, as it would likely have been visible looking north/northwest from Nolensville.