2011-04-27 MISC: AL,TN,MS,KY,OH,IN,WV,GA

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Jeff Duda

Resident meteorological expert
Staff member
Oct 7, 2008
3,260
1,966
21
Broomfield, CO
www.meteor.iastate.edu
Anyone know what the EHI values were prior to this event?
You can still check on the archived SPC mesoanalysis page for a few more days. Then you'll have to go to this site to view CONUS sized views of them. 0-1 km EHIs maxed out at 11-12 and pretty much followed along with the Tuscaloosa-Birmingham supercell during the peak hours of the event. There was quite a gradient around it, though. In far northern AL, 0-1 km EHIs were only about 2-5. 0-3 km EHIs maxed out at 15-16 in C/N MS early in the event and actually decreased slightly to 13-14 as the Tuscaloosa-Birmingham supercell was hitting those cities. Again, there was a sharp gradient away from the axis of highest values there.
 
Jan 15, 2008
38
0
5
Some more videos cropping up on Youtube I don't think have been posted yet in this thread:

Ringgold, GA:
http://www.youtube.com/watch?v=dOkKAG_obNs

Arab, AL (I think this might have been one of the Cullman tornadoes later?):
http://www.youtube.com/watch?v=J5a_yyh4KbQ

Rose Hill, MS:
http://www.youtube.com/watch?v=Yr9mO-iC9LM&feature=related

I'm curious to see the percentage of strong/violent tornadoes in this outbreak once all the confirmations and surveys are complete. I know that was a benchmark of the Super Outbreak in 1974 as well, and I think this one will be up with that previous one in that regard unfortunately.
 
Apr 27, 2010
48
0
6
Monticello, il
Some more videos cropping up on Youtube I don't think have been posted yet in this thread:

Ringgold, GA:
http://www.youtube.com/watch?v=dOkKAG_obNs

Arab, AL (I think this might have been one of the Cullman tornadoes later?):
http://www.youtube.com/watch?v=J5a_yyh4KbQ

Rose Hill, MS:
http://www.youtube.com/watch?v=Yr9mO-iC9LM&feature=related

I'm curious to see the percentage of strong/violent tornadoes in this outbreak once all the confirmations and surveys are complete. I know that was a benchmark of the Super Outbreak in 1974 as well, and I think this one will be up with that previous one in that regard unfortunately.

The Arab, AL tornado has a speaker system in the background telling people to seek shelter immediately, similar to the one that was referenced in robinson,il
 
Jun 30, 2004
330
0
5
31
Leadville, CO/ Norman, OK
Along the same lines as Mike Johnston's post, I thought I would share a couple observations about this setup. This outbreak was characterized by widespread instability combined with very strong low level shear. Low level instability was also present which I believe is a very important factor in tornado production due to the fact that a strong low level updraft is needed to stretch, and therefore intensify, existing low level vorticity. This is evident on the 18z Birmingham sounding which shows 116 J/kg of 0-3km CAPE. While this value is not exceedingly impressive, RUC forecasts suggested that 0-3km CAPE would approach 160-200 J/kg in northern AL. Either way, a modest amount of 0-3km CAPE was present on 4/27/11.

I have included a hodograph produced from the 0Z Birmingham sounding below.



It provides values of 535 m^2/s^2 for 0-1km SRH and 635 m^2/s^2 for 0-3km SRH. For comparison 5/10/10 had 0-1km SRH of 297 and 0-3km SRH of 645 in Oklahoma. Essentially the 0-1km SRH was extremely high for this event. It is also interesting to note, that out of 25 other tornado cases that I have studied, the 0-3km SRH was almost always at least 2-3 times greater than the 0-1km SRH, but that was certainly not the case on 4/27/11. The Birmingham sounding also showed approximately 66 knot winds at 1km! This is evident by the 0-1km bulk shear of 26.2 m/s given by the above hodograph (5/10/10 had 0-1km bulk shear of 15.8 m/s).

I have also included a hodograph from the 20z Okolona, MS wind profiler. Data was missing from 3-7km and from 9-10km so a great deal of interpolation was used to construct the hodograph, so it is probably relatively inaccurate. Values of 0-1km SRH were 208 and 0-3km SRH was 315.

This was undoubtedly a historic and tragic tornado outbreak. My thoughts and prayers are with all of the people who have been affected by this event.

(Note: I used storm dir/speed of 240/51, which I calculated using radar data, to produce the above values, and the SRH values are quite sensitive to changes in the direction of storm motion).
 
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DRMabe

EF1
Nov 29, 2010
99
0
6
Winston Salem NC
I wouldn't mind getting closer, but not in an urban environment. Too much room for error and getting trapped by power lines, structural debris, or just panicking drivers. Out in the wide open.....different story! lol
 
Mar 21, 2005
1,190
31
11
Kearney, NE
Death toll is now north of 310 (heard one report of 313). That puts it at No. 6 on the All-Time Killers list and ahead of the 3-4 Apr 1974 MI/IL/IN/OH/KY/TN/WV/VA/MS/AL/GA/NC outbreak. If it reaches 331 (sadly a distinct possiblility) it would claim the No. 3 spot. Even with "only" reaching number 3 on the death toll list I believe that given that the two events ahead of it were in 1936 and 1925, the death toll numbers in this age of NEXRAD radars and early warnings make this the worst tornado outbreak of all time - put into that perspective.
 

E. Clark

EF0
Mar 18, 2010
48
0
5
Currently - Tahoe area
I shouldn't be paying for that. The users/owners of the building should be. If it was important enough for those survivors, they would have taken the initiative on their own.

Also remember than 70% of all warnings do not verify, and even out of the ones that do they only impact 1% of the target audience. So a LARGE majority of the time, this internal EBS is going to alert you to something that doesn't occur. Won't take too long before those wires get snipped ;)



That costs a LOT more money. Is the electric company going to eat that? Should I subsidize your electric bill? Or should you pay for underground if you want underground?
As I said - we have paid trillions for 'security' type safety measures. And because of this, in part, they are cutting budgets on real safety measures that are possibly needed several times a year.
And insofar as underground being more expensive. Yes it is a more expensive initial outlay- but it is proven that it is cheaper in the long run when you add in repair costs over time. To make it simple- it is the difference between paying for a cheap blender and replacing it constantly - or buying a more expensive one that lasts 10 years. I would rather invest in something solid that isn't going to blow over in the first strong wind. I think logically, most people would.
God only knows how much these repairs are going to cost when added up- just for power infrastructure repair alone.
 

E. Clark

EF0
Mar 18, 2010
48
0
5
Currently - Tahoe area
The Arab, AL tornado has a speaker system in the background telling people to seek shelter immediately, similar to the one that was referenced in robinson,il
Wow! That is exactly what I am talking about! It is an old and true psychological principle that people will 'alert' and focus to the sound of a voice long before a 'tone'. I am sure the Japanese were taking that into account with their warning system, and apparently the smart people of Arab, Al did as well.
 

rdale

EF5
Mar 1, 2004
7,212
769
21
50
Lansing, MI
skywatch.org
As I said - we have paid trillions for 'security' type safety measures. And because of this, in part, they are cutting budgets on real safety measures that are possibly needed several times a year.
On the other hand - how many terrorist attacks have we stopped in the last 10 years? A lot! Some with much larger potential impacts than a tornado outbreak.

And insofar as underground being more expensive. Yes it is a more expensive initial outlay- but it is proven that it is cheaper in the long run when you add in repair costs over time.
Absolutely wrong. The power poles outside my house have been here for decades. Take the number of poles in existence versus the number damaged per year - and I think you'll get a different outcome ;)


It is an old and true psychological principle that people will 'alert' and focus to the sound of a voice long before a 'tone'.
That would be a little more believable conclusion if there weren't stories about "I watched it on TV, and they mentioned my town, but I didn't think it would hit me." There is more to the story than siren vs voice.
 

E. Clark

EF0
Mar 18, 2010
48
0
5
Currently - Tahoe area
I don't know if this has been posted in this thread yet- but here is another view of the Tornado that hit Arab AL. http://www.youtube.com/watch?v=tVoTAfEQ8C0 - it is, like the Tuscaloosa/BMH torn a violent multi-vortex with horizontals. Apparently we had twinning with this one at one point: "One resident in the Ruth community was near Marshall Medical Center North on Alabama 69 between Arab and Guntersville when he looked toward Union Grove. He said he saw two different tornadoes, one behind the other, the lead twister much bigger."

Also in the story is the detail of the 5 deaths in the area:
"Just down the road from Johnson's home, five lives were lost. According to neighbors, the home the victims huddled inside was blown off its foundation, across a ravine and splattered about 150 yards - not just smashed by the tornado but dragged along its path."

So apparently this family was trying to take cover but the torn overpowered what structure they had.
 

E. Clark

EF0
Mar 18, 2010
48
0
5
Currently - Tahoe area
On the other hand - how many terrorist attacks have we stopped in the last 10 years? A lot! Some with much larger potential impacts than a tornado outbreak.



Absolutely wrong. The power poles outside my house have been here for decades. Take the number of poles in existence versus the number damaged per year - and I think you'll get a different outcome ;)




That would be a little more believable conclusion if there weren't stories about "I watched it on TV, and they mentioned my town, but I didn't think it would hit me." There is more to the story than siren vs voice.
1. The conclusion about voice alert getting faster attention than 'tone' alerts is the reason that every time you fly- if something goes wrong with a control on the plane- the pilot gets a voice command rather than a tone. Call the FAA and the US Airforce and tell them their decision to insert voice alert/commands is based on 'not believable conclusions'.

2. You cannot base a decision about an entire countries infrastructure on the condition of two telephone poles in Lansing Michigan.

3. How many terrorist attacks have we stopped? No one knows. Probably nil. But I know how many died this week from storms. And last year. And the year before that. I would guess the probability is much higher.
 

rdale

EF5
Mar 1, 2004
7,212
769
21
50
Lansing, MI
skywatch.org
1. The conclusion about voice alert getting faster attention than 'tone' alerts
Is because people can hear a siren and know what it means right off the bat. They don't have to struggle to hear the message, they know that on a stormy day - the tornado siren means one thing only. I'm not sure I understand how this is related to cockpit management?

2. You cannot base a decision about an entire countries infrastructure on the condition of two telephone poles in Lansing Michigan.
Of course not. That's why I asked you how many power poles there are in the US versus how many are damaged annually...

3. How many terrorist attacks have we stopped? No one knows. Probably nil.
Not I see you're just trolling.
 
Feb 14, 2005
879
22
11
Charleston, South Carolina
Death toll is now north of 310 (heard one report of 313). That puts it at No. 6 on the All-Time Killers list and ahead of the 3-4 Apr 1974 MI/IL/IN/OH/KY/TN/WV/VA/MS/AL/GA/NC outbreak. If it reaches 331 (sadly a distinct possiblility) it would claim the No. 3 spot. Even with "only" reaching number 3 on the death toll list I believe that given that the two events ahead of it were in 1936 and 1925, the death toll numbers in this age of NEXRAD radars and early warnings make this the worst tornado outbreak of all time - put into that perspective.
Wikipedia lists the death toll from the Super Outbreak as a range from 315-330, and the detailed list of deaths by state totalling 319. 9 of those deaths were in the province of Ontario, Canada so I'm not sure whether you were including those in determining your ranking. Looks like there was some uncertainty on the death toll. By any measure, it's going to be very close as to whether the instant outbreak will surpass the Super Outbreak.

EDIT: Mike Smith, I'm sure you are critically interested in the outcomes of this event given your research and interest in the evolution of the warning system, so we would appreciate any preliminary insights you might have.
 
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Jun 24, 2004
137
0
0
48
Tyler, TX
According to this 335 people lost their lives in the Super Outbreak. Seems there are lots of differnet death totals out there for that event. If you are interested I have a few thoughts on how we the Media, yes I said we even though I try to make them state the facts, continues to get the tornado count wrong here. To all of you that chased this event and gave valuable life saving information, thank you!
 
Mar 1, 2007
58
0
5
Valencia, CA
1. The conclusion about voice alert getting faster attention than 'tone' alerts is the reason that every time you fly- if something goes wrong with a control on the plane- the pilot gets a voice command rather than a tone. Call the FAA and the US Airforce and tell them their decision to insert voice alert/commands is based on 'not believable conclusions'.

2. You cannot base a decision about an entire countries infrastructure on the condition of two telephone poles in Lansing Michigan.

3. How many terrorist attacks have we stopped? No one knows. Probably nil. But I know how many died this week from storms. And last year. And the year before that. I would guess the probability is much higher.
So, what do you say for the people who sought shelter after hearing the sirens, but were still killed? At what point do you say that an event of this magnitude will kill people no matter how much advanced warning is given? Do you say that the govt. needs to provide everyone with a shelter below ground for situations where the tornadoes are so violent?

The important question is how many lives were saved because of the warning systems, the advanced SPC forecasts, radar and the spotters on the ground? I would imagine that number is large, but obviously there is no way to know. Just my 2 cents...