2011-05-22 Joplin, MO tornado thread

[Aaron Kafton]

Thought some of you would find this interesting. Civil engineer finally released their study of the Joplin tornado damage. Most of the damage was actually caused by EF-2 level wind speeds, some EF-3 speeds and a little EF-4 but no EF-5 damage to speak of. Most of the damage was caused because apparently a lot of our homes weren't even bolted to the foundation and even those that were had poorly connected roofs.
http://www.joplinglobe.com/tornadom...ineers-release-study-of-Joplin-tornado-damage

 

[Elaine Spencer]

The National Institute of Standards and Technology (NIST) has just released its draft report on Joplin:

http://www.nist.gov/el/disasterstudies/joplin-112113.cfm

http://www.nist.gov/customcf/get_pdf.cfm?pub_id=914787 (link to PDF file of actual report)

It's more than 400 pages long but contains info on just about every aspect of the disaster -- the warning process, structural damage, cause/locations of deaths and injuries, etc.

NIST will accept public comment on the report through Jan. 6, after which they will release a final version. Although NIST is not a rulemaking agency, its recommendations often find their way into state and federal regulations, safety and building codes, etc.

 

[Brian McWatters]

Hey guys, I just got done writing a blog post about the Joplin tornado and I'd love some feedback on it. Between family issues and researching it took a loooong time to finish, so to be honest I didn't even proofread it. I'm sure there are mistakes, so if anyone reads it please feel free to let me know if I messed something up.

http://stormstalker.wordpress.com/2013/02/13/joplin/

Shawn,

I liked your article, and the pictures are excellent. But there is one mistake I saw. Your article says the sirens in Joplin sounded for the second time at 5:31 PM. But according to Mike Smith's "When the Sirens Were Silent" it was 5:38 PM when the sirens sounded for the second time. At 5:38 the tornado had been on the ground for four minutes and it was already doing EF-4 damage. It was three minutes later at 5:41 that the tornado crossed into the Joplin city limits. So when those sirens sounded that second time, the residents of south Joplin had roughly 3 to 6 minutes to find shelter. The timing of the second siren alert was very likely a factor in the number of deaths and injuries that occurred.

The video below from KSNF-TV Joplin confirms that the tornado was on the ground doing damage when the sirens sounded the second time.

http://www.youtube.com/watch?v=yDOLjlzQYSs

 

[Shawn Schuman]

Shawn,

I liked your article, and the pictures are excellent. But there is one mistake I saw. Your article says the sirens in Joplin sounded for the second time at 5:31 PM. But according to Mike Smith's "When the Sirens Were Silent" it was 5:38 PM when the sirens sounded for the second time. At 5:38 the tornado had been on the ground for four minutes and it was already doing EF-4 damage. It was three minutes later at 5:41 that the tornado crossed into the Joplin city limits. So when those sirens sounded that second time, the residents of south Joplin had roughly 3 to 6 minutes to find shelter. The timing of the second siren alert was very likely a factor in the number of deaths and injuries that occurred.

The video below from KSNF-TV Joplin confirms that the tornado was on the ground doing damage when the sirens sounded the second time.

http://www.youtube.com/watch?v=yDOLjlzQYSs

Thank you Brian. That was one detail I wasn't sure on at the time, because I'd seen both 5:31 and 5:38 as the time when the sirens were activated a second time. Most sources, both newspapers and official documents, stated that it was 5:31 when the second sirens sounded. After doing some more digging I began to suspect that the 5:31 figure was either mistaken or deliberately manipulated. A member of another forum who was in Joplin when the tornado struck also mentioned that he thought the siren had sounded several minutes later, and that video would seem to confirm those suspicions. I haven't read Mike's book, but I may pick up a copy at some point.

Anyhow, I have another mistake in that article that needs to be corrected, so I'll update that portion as well.

 

[Mike Smith]

The second siren activation was from 5:38 to 5:41pm. That is confirmed from multiple sources and videos.

Jeff Piotrowski's plea to activate the sirens at 5:36pm was the reason the sirens were activated two minutes later.

There was no siren activation at 5:31pm.

 

[Bob Schafer]

This seems to be a new video. It was just posted June 1, and everyone should watch it:

 

[Tim Paitz]

I wonder why they never issued a tornado emergency..... wasn't it because of the fact that it touched down just outside Joplin along the JJ highway?

 

[rdale]

As I recall 2012 is when the TE became a formal NWS product.

 

[Pete Kustra]

This tornado might not have been as violent as the Tanner, AL tornado on April 27 or the El Reno, OK tornado on May 24, but just speaking in terms of the sheer destruction and misery it left in its path, it was definitely the worst of 2011.

P.S. Did it actually reach 250 mph winds, or was that just media sensationalism? Most sources seem to be saying that peak winds were around 210 mph.

 

[Shawn Schuman]

P.S. Did it actually reach 250 mph winds, or was that just media sensationalism? Most sources seem to be saying that peak winds were around 210 mph.

There are articles that claimed the 250 mph estimate came from the NWS, but I've never seen anything official in that regard. Partha Sarkar, an engineering professor from Iowa State, calculated that the parking stops would've required winds above 205 mph to be lifted up and lofted as they were, but that's the only "official" number I've seen other than the NWS' generic "greater than 200 mph" survey estimate.

That said, I'm of the opinion that the winds in the most violent of tornadoes often far exceed 200 mph, and Joplin certain fits that description. If the winds were > 205 mph just a few inches above ground level, it's not hard to imagine the winds being significantly stronger at a height of a couple meters.

 

[Pete Kustra]

That said, I'm of the opinion that the winds in the most violent of tornadoes often far exceed 200 mph.

It seems very possible. Honestly if every tornado that exceeded 200 mph was rated EF5, we'd probably see several every year. 2011 might have seen 10 or even 15, while even 2013 might have seen three or four (Moore, Bennington, El Reno, and possibly New Minden).

 

[Tim Paitz]

As I recall 2012 is when the TE became a formal NWS product.

I thought they started issuing PDS tornado warnings starting with April 14th, 2012. Then again, that was when it was still experimental.

 

[rdale]

There's no such thing as a PDS warning. Those are watches.

 

[Paul Knightley]

True, although the wording is sometimes used, it's not given the moniker, 'PDS'.

 

[Brian G]

The Impact Based Warning changes, which are still being rolled out, define threat categories for tornadoes now. For tornadoes in which the threat is "considerable" or "catastrophic" will get the PDS wording added to them. I have seen other's use the PDS moniker when referring to these new warnings. Now, whether or not that should be considered official lexicon like what we do with PDS watches...I don't know. It looks like many of the NWS offices would have started using the new tags after April 1st of this year.

As a side note, I believe the GRLevelX products are using these new tags.