Mayflower-Vilonia tornado of 2014

[Chinook]

I've been looking at some various case studies of tornadoes/outbreaks on Youtube. I just took a quick search of Youtube and also the internet in general, and not a whole lot has been said about the devastating Mayflower-Vilonia tornado (9 years ago).  The Mayflower-Vilonia tornado was 41 miles long and started near 0000z and continued for about 1 hour. It was the only tornado in Arkansas on April 27, 2014.  Storm reports and tornadoes were widely spread out within the Moderate risk segment in Arkansas and Missouri. (note: HIGH RISK issued at 20z in Arkansas) On April 28, there were dozens of tornadoes in that day's Moderate risk segment. back to April 27th: There was CAPE up to 3000 J/kg in southern Arkansas with a stationary front  near Little Rock. With the easterly winds north of Little Rock, 0-3km SRH maxed out at a large value of 600 m2/s2. (Also supported by Little Rock special sounding at 21z, 612 m2/s2)

 

[andyhb]

It was an EF5. That is all.

[Quincy]

That was my first tornado. I did a terrible job trying to chase and document it, even though I was directly in front of it. With El Reno recently in mind and my inexperience, I bailed north(?!) at the last minute, thinking I’d be cutting it too close if I went southeast. I probably could have made it, but being new and extra cautious, I bailed. Knowing what I know now, I would have continued southeast another exit or two, instead of getting off in Mayflower. Then I would have probably gotten some incredible footage from the immediate southeast.

To this day, the radar signature remains as the most impressive I’ve ever chased, let alone have been a couple of miles away from.

It’s a great example of a warm front near the Arkansas River valley enhancing the channeling of low level flow. Always beware a warm front draped from NW/WNW to SE/ESE across central Arkansas. We’ve seen those setups produce prolific tornadoes before. 

The 00z LZK sounding is also one of the best sampled, regularly scheduled RAOBs you’ll ever see for a violent tornado, being in close proximity to the tornado in time and distance:

[Santa Clause]

Ef 5…but they don’t exist anymore

 

[Chinook]

13 hours ago, andyhb said:

It was an EF5. That is all.

The SPC research page only says EF-4. I wonder why that is wrong. It's not like it happened yesterday.

Other information that I didn't post. I discovered that the supercell must have started close to the stationary front and tracked to the cool side of it. The cell must have been using the most unstable layer (MUCAPE) to power up the huge updrafts. As you can see, the mesoanalysis surface-based CAPE was close to zero with the colder air, and apparently this didn't stop the system from creating a huge tornado.

[andyhb]

20 minutes ago, Chinook said:

The SPC research page only says EF-4. I wonder why that is wrong. It's not like it happened yesterday.

Other information that I didn't post. I discovered that the supercell must have started close to the stationary front and tracked to the cool side of it. The cell must have been using the most unstable layer (MUCAPE) to power up the huge updrafts. As you can see, the mesoanalysis surface-based CAPE was close to zero with the colder air, and apparently this didn't stop the system from creating a huge tornado.

This is partially a meme at this point, but the survey was very questionable to say the least. There were a large number of damage indicators ignored. Additionally, there were a couple of houses that are listed in DAT that qualified as EF5 candidates – but were not given such ratings due to some pretty impressive nitpicking – to the point of John Robinson (WCM of NWS Little Rock at the time) saying that some on the committee developing the EF-scale essentially didn't want houses being rated EF5.

[cgidd8]

First and last chase in Arkansas was Mayflower 2014. I was sufficiently warned seeing the destruction along I-40 near Mayflower that chasing with Arkansas' lack of site-lines and difficult road network is playing with fire. Easily the worst tornado damage I've ever witnessed in person.

[Chinook]

I pulled up the archived Level-3 radar data a couple of days ago, so that's what you see here. Somehow, my vast amount of saved data didn't contain this, although I remember looking at this radar data as it happened. It probably because I had some data lost when I had two laptop crashes between 2013-2015, but thankfully a lot of my data is backed up in various formats (like CDROMS from the old days).

[CheeselandSkies]

10 hours ago, Quincy said:

That was my first tornado. I did a terrible job trying to chase and document it, even though I was directly in front of it. With El Reno recently in mind and my inexperience, I bailed north(?!) at the last minute, thinking I’d be cutting it too close if I went southeast. I probably could have made it, but being new and extra cautious, I bailed. Knowing what I know now, I would have continued southeast another exit or two, instead of getting off in Mayflower. Then I would have probably gotten some incredible footage from the immediate southeast.

To this day, the radar signature remains as the most impressive I’ve ever chased, let alone have been a couple of miles away from.

It’s a great example of a warm front near the Arkansas River valley enhancing the channeling of low level flow. Always beware a warm front draped from NW/WNW to SE/ESE across central Arkansas. We’ve seen those setups produce prolific tornadoes before. 

The 00z LZK sounding is also one of the best sampled, regularly scheduled RAOBs you’ll ever see for a violent tornado, being in close proximity to the tornado in time and distance:

This is something I just learned recently from watching Trey Greenwood's videos but this is a good, stark example here. The hodograph shape will resemble the radar structure of supercells that form in the shear environment it represents. We can see how the hodograph folds back on itself in the upper levels, and thus how the storm's forward-flank core curls out ahead of the tornado's path. This can make for not-great viewing conditions even though the rear flank is fairly well separated from the core and not "rain-wrapped" in the stereotypical HP fashion. Something similar was observed at Louisville, MS the following day.

OTOH the storm I chased in Iowa on March 31 formed in an environment with much less clockwise curvature in the upper levels, the hodograph went straight out to the northeast and very little rain fell in the eventual path of the tornado as the storm's core skirted by to the north.

[Chinook]

1 hour ago, CheeselandSkies said:

This is something I just learned recently from watching Trey Greenwood's videos but this is a good, stark example here. The hodograph shape will resemble the radar structure of supercells that form in the shear environment it represents. We can see how the hodograph folds back on itself in the upper levels, and thus how the storm's forward-flank core curls out ahead of the tornado's path. This can make for not-great viewing conditions even though the rear flank is fairly well separated from the core and not "rain-wrapped" in the stereotypical HP fashion. Something similar was observed at Louisville, MS the following day.

OTOH the storm I chased in Iowa on March 31 formed in an environment with much less clockwise curvature in the upper levels, the hodograph went straight out to the northeast and very little rain fell in the eventual path of the tornado as the storm's core skirted by to the north.

It took me perhaps a very long time to figure out that the degree of 0-6 km shear (and layers above 0-6km) directly related to the amount of stretching out of the FFD and also the extent to which the anvil or cirrus material is carried away from the storm. And along with that, the storms with greater 0-3km storm relative helicity but less impressive 0-6km shear, such as 30 kt or 35 kt, turned out to be high precip. as the higher level winds did not remove material. I'm saying this because sometimes you just have to do something for years to learn it. Or you could have "Convective Chronicles" say it in a pretty easy way to understand.

[cheese007]

21 hours ago, andyhb said:

to the point of John Robinson (WCM of NWS Little Rock at the time) saying that some on the committee developing the EF-scale essentially didn't want houses being rated EF5.

Can you explain this a little more/link to what you're talking about? What's the issue with houses being rated EF-5?

[andyhb]

3 hours ago, cheese007 said:

Can you explain this a little more/link to what you're talking about? What's the issue with houses being rated EF-5?

https://arktimes.com/arkansas-blog/2014/05/05/meteorologist-defends-ef4-rating-on-vilonia-tornado

Quote

Here’s something to keep in mind: First and foremost, if a house that has a foundation built with nuts, bolts, and appropriate-sized washers is swept away, leaving only the concrete foundation, the “expected value” of wind in the Enhanced Fujita Scale is 200 mph, which puts it at the top of the EF4 category, not an EF5. It would have to be an exceptionally well-built house to go over 200 mph and thus achieve an EF5.

It’s my understanding that when the Enhanced Fujita Scale was put together this was done for a very specific reason — that some on the committee felt that a house should never be rated EF5. The final outcome was that the “expected value” was placed so that it would be very rare that a house could be rated EF5.

[CheeselandSkies]

7 hours ago, andyhb said:

https://arktimes.com/arkansas-blog/2014/05/05/meteorologist-defends-ef4-rating-on-vilonia-tornado

This is getting into a whole OT can of worms but IMO this is bogus because it was said when the EF-scale was adopted that it would be a 1:1 changeover from the original Fujita scale, I.E. an F0 then would be an EF0 now, and so on all the way on up. Obviously in practice that's not true because the definitive descriptor of F5 damage was "strong frame houses lifted off foundations and carried considerable distances to disintegrate...". Now of course, not all frame houses are created equal and "strong" is subjective so applying some engineering standards and scientific rigor isn't a bad idea, but the pendulum has swung too far, in some cases very much too far in that direction.

Now, I agree with @andyhb that Vilonia 2014 is the most egregious case of this (just ahead of Chickasha and Goldsby, OK 5/24/2011), and set a bad precedent to the point where it's gone way beyond the understandable challenges with determining the difference between EF4 and EF5 based on the engineering quality of a structure that no longer exists, and resulted in suspiciously lowballed ratings much further down the scale (to the point where in some cases we've seen the sweeping away of frame homes initially rated as low as EF2, which is outside the bounds of the scale, before being "corrected" to low-end EF3).

[andyhb]

That entire article/response is full of subjective nonsense that isn't consistent with the original scale.

I wrote something along these lines elsewhere: It's like the mentality has changed from "this house appears to be F5/EF5, now let's look at the surrounding context to make sure that is confirmed" to something like "this house is EF4, now let's look at the surrounding context to make sure it shouldn't be EF5", which are two very different statements.

It's because of that EXP Bound DOD 10 being 200 mph EF4 that this is happening.

[Santa Clause]

A bit OT but that story about the son texting the mom remains one of the saddest to come from any of these events. Just ugh.

[RCNYILWX]

That entire article/response is full of subjective nonsense that isn't consistent with the original scale.
I wrote something along these lines elsewhere: It's like the mentality has changed from "this house appears to be F5/EF5, now let's look at the surrounding context to make sure that is confirmed" to something like "this house is EF4, now let's look at the surrounding context to make sure it shouldn't be EF5", which are two very different statements.
It's because of that EXP Bound DOD 10 being 200 mph EF4 that this is happening.

To the supposed lack of EF-5s since Moore, if EF-5 were adjusted down to 190+ mph, we'd have seen the "normal" amount of EF-5s over the past 10 years. Particularly with that DI and DOD for houses.

As an NWS employee, I think that the agency as a whole has lost the plot when it comes to damage ratings. Having some reference to engineering standards is all well and good, but an impossible standard to reach EF-5 has been set based off building codes that don't exist in much of the country.

We've become fixated on finding everything a tornado didn't do as opposed to judging what a tornado did do with respect to totality of damage. If a large swath of a town has catastrophic destruction, it's not the town's fault if they don't have structures built to withstand >200 mph winds. The lower bound on the DIs is used too liberally imo.

Vilonia is an example less than a year after Moore of a tornado that by all accounts should have been rated EF-5. Prior to that, there's a good case to be made that Tuscaloosa 2011 should have been EF-5. On the flipside of that, it seems likely that the post-Moore survey standards would have yielded at least a few less EF-5s on April 27, 2011.

In recent years, I think Mayflower is probably the best example of how the pendulum has swung well too far in the direction of assigning impossible engineering standards to reach EF-5.

Hopefully, the forthcoming updates to the EF scale help bring things back to a more reasonable/realistic place.

[CheeselandSkies]

7 hours ago, RCNYILWX said:

To the supposed lack of EF-5s since Moore, if EF-5 were adjusted down to 190+ mph, we'd have seen the "normal" amount of EF-5s over the past 10 years. Particularly with that DI and DOD for houses.

As an NWS employee, I think that the agency as a whole has lost the plot when it comes to damage ratings. Having some reference to engineering standards is all well and good, but an impossible standard to reach EF-5 has been set based off building codes that don't exist in much of the country.

We've become fixated on finding everything a tornado didn't do as opposed to judging what a tornado did do with respect to totality of damage. If a large swath of a town has catastrophic destruction, it's not the town's fault if they don't have structures built to withstand >200 mph winds. The lower bound on the DIs is used too liberally imo.

Vilonia is an example less than a year after Moore of a tornado that by all accounts should have been rated EF-5. Prior to that, there's a good case to be made that Tuscaloosa 2011 should have been EF-5. On the flipside of that, it seems likely that the post-Moore survey standards would have yielded at least a few less EF-5s on April 27, 2011.

In recent years, I think Mayflower is probably the best example of how the pendulum has swung well too far in the direction of assigning impossible engineering standards to reach EF-5.

Hopefully, the forthcoming updates to the EF scale help bring things back to a more reasonable/realistic place.


 

This guy right here.

[Normandy]

Great post.  Damage ratings and tornado intensity science is just strange to me.  Another example (albeit not related to this tornado) is the el Reno tornado being rated EF-3 when there were radar velocities suggesting EF-5 intensity.  It seems as if we selectively choose data and ignore other data to rate these tornadoes.

[andyhb]

15 hours ago, RCNYILWX said:

To the supposed lack of EF-5s since Moore, if EF-5 were adjusted down to 190+ mph, we'd have seen the "normal" amount of EF-5s over the past 10 years. Particularly with that DI and DOD for houses.

As an NWS employee, I think that the agency as a whole has lost the plot when it comes to damage ratings. Having some reference to engineering standards is all well and good, but an impossible standard to reach EF-5 has been set based off building codes that don't exist in much of the country.

We've become fixated on finding everything a tornado didn't do as opposed to judging what a tornado did do with respect to totality of damage. If a large swath of a town has catastrophic destruction, it's not the town's fault if they don't have structures built to withstand >200 mph winds. The lower bound on the DIs is used too liberally imo.

Vilonia is an example less than a year after Moore of a tornado that by all accounts should have been rated EF-5. Prior to that, there's a good case to be made that Tuscaloosa 2011 should have been EF-5. On the flipside of that, it seems likely that the post-Moore survey standards would have yielded at least a few less EF-5s on April 27, 2011.

In recent years, I think Mayflower is probably the best example of how the pendulum has swung well too far in the direction of assigning impossible engineering standards to reach EF-5.

Hopefully, the forthcoming updates to the EF scale help bring things back to a more reasonable/realistic place.

Glad to see we're on the same page here, great post.

I would really like to know the rationale behind "houses shouldn't be rated EF5" when they are, by far, the most common DIs that receive EF4-EF5 level damage. There's this centralization to cities that seems to be occurring with the EF5 rating where only high rises, shopping malls, and institutional buildings can get an EF5 rating at EXP bound, which essentially eliminates them from the climatology if that standard is followed.

The other frustrating thing is seeing higher ups in NOAA or the academic community saying "who cares" or chastising people questioning the ratings (obviously trolls excluded here) when anyone with a decent knowledge and/or has been following along can tell that something weird is going on when there's an EF5 drought of nearly 10 years. Climatology and observed events suggest that shouldn't happen, and it probably shouldn't have happened with the Bridge Creek/Moore '99 to Greensburg drought either.

[CheeselandSkies]

@andyhb Exactly. There's been a lot more discussion/debate-sometimes-verging into trolling about this topic on the "other forum", but what exactly are we trying to accomplish here? Are we trying to rate tornadoes to determine how strong they get, how often, where, and when (which is what I once thought); or to prove...what, exactly about construction engineering around the USA?

[andyhb]

Should probably add that both Chickasha and Goldsby from 5/24/2011 in OK should probably be EF5s as well.

[RCNYILWX]

Should probably add that both Chickasha and Goldsby from 5/24/2011 in OK should probably be EF5s as well.

I feel confident in saying that Rochelle-Fairdale on April 9, 2015 was also an EF-5. The wind rowing in the aerial photo from IEMA Air-One looks strikingly similar to that seen in some of the April 27th tornadoes. The survey process for that tornado was rushed imo - we never had an in person QRT consultation, just a virtual one. I'm not sure how that was decided upon, if the QRT felt comfortable going virtual or our since retired MIC pushed for a faster decision to stick with high end EF-4.

[RCNYILWX]

One of the turning points in how the pendulum has swung toward too stringent an EF-5 standard was the engineering assessment in the wake of the Joplin tornado. I I'm not mistaken, that assessment found that hardly any/none of the destroyed homes would have withstood EF-3 winds. It seems like, despite Moore receiving an EF-5 designation, that since that Joplin engineering assessment, there's been a granular focus on home construction vs. coverage of damage DI 10 with the highest DOD.

Sent from my SM-G998U using Tapatalk

[andyhb]

1 hour ago, RCNYILWX said:

I feel confident in saying that Rochelle-Fairdale on April 9, 2015 was also an EF-5. The wind rowing in the aerial photo from IEMA Air-One looks strikingly similar to that seen in some of the April 27th tornadoes. The survey process for that tornado was rushed imo - we never had an in person QRT consultation, just a virtual one. I'm not sure how that was decided upon, if the QRT felt comfortable going virtual or our since retired MIC pushed for a faster decision to stick with high end EF-4.

And so the million dollar question is, of course, "why"?

I have strong suspicion that a similar thing happened with Vilonia. Some of this stuff seems down to personal/office politics. Of course this is emphasized by that quote suggesting that "some on the development team for the EF-scale felt that a house should never be given an EF5 rating".

[andyhb]

4 hours ago, CheeselandSkies said:

@andyhb Exactly. There's been a lot more discussion/debate-sometimes-verging into trolling about this topic on the "other forum", but what exactly are we trying to accomplish here? Are we trying to rate tornadoes to determine how strong they get, how often, where, and when (which is what I once thought); or to prove...what, exactly about construction engineering around the USA?

But at the same time, there is a clear subset who wants to have some sort of constructive discussion regarding the topic, but I feel as though some who have expertise in the field do not. That's all well and good, but there's going to keep being questions until some answers are found, and saying "who cares" isn't really a response.

[andyhb]

3 hours ago, RCNYILWX said:

One of the turning points in how the pendulum has swung toward too stringent an EF-5 standard was the engineering assessment in the wake of the Joplin tornado. I I'm not mistaken, that assessment found that hardly any/none of the destroyed homes would have withstood EF-3 winds. It seems like, despite Moore receiving an EF-5 designation, that since that Joplin engineering assessment, there's been a granular focus on home construction vs. coverage of damage DI 10 with the highest DOD.

Sent from my SM-G998U using Tapatalk
 

To this exact point, this is from the ASCE report on Joplin...

Quote

The team found no evidence of building damage from winds at 200 mph or greater, the minimum threshold for an EF-5. The study concluded that EF-5 ratings were nearly impossible to observe given the high construction quality threshold that must be met for determining that level of wind speed.

[nwohweather]

To the supposed lack of EF-5s since Moore, if EF-5 were adjusted down to 190+ mph, we'd have seen the "normal" amount of EF-5s over the past 10 years. Particularly with that DI and DOD for houses.

As an NWS employee, I think that the agency as a whole has lost the plot when it comes to damage ratings. Having some reference to engineering standards is all well and good, but an impossible standard to reach EF-5 has been set based off building codes that don't exist in much of the country.

We've become fixated on finding everything a tornado didn't do as opposed to judging what a tornado did do with respect to totality of damage. If a large swath of a town has catastrophic destruction, it's not the town's fault if they don't have structures built to withstand >200 mph winds. The lower bound on the DIs is used too liberally imo.

Vilonia is an example less than a year after Moore of a tornado that by all accounts should have been rated EF-5. Prior to that, there's a good case to be made that Tuscaloosa 2011 should have been EF-5. On the flipside of that, it seems likely that the post-Moore survey standards would have yielded at least a few less EF-5s on April 27, 2011.

In recent years, I think Mayflower is probably the best example of how the pendulum has swung well too far in the direction of assigning impossible engineering standards to reach EF-5.

Hopefully, the forthcoming updates to the EF scale help bring things back to a more reasonable/realistic place.

Really well said. Vilonia and Mayfield are two obvious situations of a likely EF5 in my opinion. Mayfield probably had the most airborne debris signatures I’ve ever seen, and a track of almost 200 miles. How a mesocyclone that sustaining wasn’t an EF5 is beyond me

[andyhb]

Just to reinforce the poor nature of the survey here, none of these structures in Vilonia were given DIs (reposted from another forum) except for the top image where they were given a "blanket" rating of EF3, i.e. the individual DIs were not rated as separate entities.

This doesn't even include an entire neighborhood of homes along Cemetery Street south/southwest of downtown that was devastated, all of which had no DIs assigned. This overhead shot looking east with Main Street at left-center and Cemetery Street as the main N-S road at the center-foreground shows the extent of the high end damage in this area. The wind rowing here might be worse than that Rochelle picture you shared @RCNYILWX. I fail to see why the survey team would not assign DIs to this area considering that most buildings along Main Street were surveyed. I spy at least a half dozen EF5 candidates in that neighborhood alone pending construction, and all of them look like EF4 candidates at least.

[Normandy]

What’s even more maddening to me is their description of EF-5.  The wording they use they don’t even follow during their damage assessment.  It does not mention these anchor bolts they always use as reason to not give the EF-5 rating.  If they would just simply follow their own words as a guide would immediately get better results when rating these tornadoes.

[cstrunk]

They ought to just stick to the EF-5 description for ratings and if they want to apply super-strict construction engineering criteria, reserve that for a new EF-6 category. That'll cause a stir.