Enhanced Fujita Scale (again?)

[scott r currens]

For the first time I read through all 28 of the damage indicators on the new EF-scale. I was very surprised to see that a well-build, securely anchored, single-family-home has a maximum EF rating of EF4. Am I missing something? Isn’t this a significant change from the original Fujita Scale?

http://www.spc.noaa.gov/efscale/ef-scale.html

The following is a list of damage indicators and damage descriptions that indicate an EF-5 on the Enhanced Fujita scale.

LOWER LIMITS = EF-5
None

EXPECTED LIMITS = EF-5
11. Large Shopping Mall (LSM) – Complete destruction of all or a large section of the building. EXP 204 LB 176 UP 247
18. Mid-Rise Building: 5-20 Stories (MROB) – Permanent structural deformation. EXP 210 LB 181 UB 268
19. High-Rise Building: Greater than 20 Stories (HROB) – Significant structural deformation. EXP 228 LB 190 UB 290
20. Institutional Building (IB) – Significant damage to building envelope. EXP 210 LB 178 UB 268

UPPER LIMITS = EF-5
5. Apartments, Condominiums and Townhouses (ACT) (Three stories or less) – Almost total destruction of top two stories. EXP 180 LB 155 UB 205
6. Motels (M) – Total destruction of entire building. EXP 190 LB 163 UB 217
7. Masonry Apartments or Motels (MAM) – Total destruction of a large section of building. EXP 180 LB 160 UB 205
9. Small Professional Building (SPB) (Single story, less than 5000 square ft) – Total destruction of entire building. EXP 157 LB 148 UB 200
12. Large Isolated Retail Building (LIRB) – Complete destruction of all or a large section of the building. EXP 110 LB 147 UB 201
15. Elementary School (ES) – Total destruction of a large section of building or entire building. EXP 176 LB 152 UB 203
16. Junior or Senior High School (JHSH) – Total destruction of a large section of building envelope. EXP 192 LB 163 UB 224
17. Low-Rise Building: 1-4 Stories (LRB) – Complete destruction of all or a large section of building. EXP 188 LB 161 UB 221
[/QUOTE]
Given the new set of damage indicators what tornadoes that were rated F5 in the past would be rated EF5 today?

What about the Bridge Creek/Moore F5 or the Jarrell F5? I believe that the only structures rated F5 were single family homes. If I am wrong please let me know.

 

[Jeff Snyder]

The latest revision includes an EF5 rating for family residence damage indicator. I think Greg Stumpf posted about this in the past, but I remember hearing about it at November's SLS Conference as well. Read "Revision 2" (Oct. 10 2006) of the report at http://www.wind.ttu.edu/EFScale.pdf (the family residence DI is on page 25 of the PDF, or page A-2 of the report)...

EDIT: Actually, the expected wind speed for DoD 10 is 200mph, which is the upper-most bound of EF4, if I'm not mistaken. The range of windspeed, however, is 165-220mph, so an upward adjustment to the "expected" windspeed for DoD10 would bring it into the EF5 category. I think there have been modifications to other DIs and DoDs in the latest revision.

 

[scott r currens]

That is much better Jeff. Thanks

 

[Alexandre Aguiar]

Can anyone solve this doubt ? The damage descriptions considers the kind of structures and constructions that exist in the United States. Just one example. Here in South America, one of the most tornadic areas of the world, there are no mobile homes. Every country has its particular construction code and buildings and homes may be more as solid in some nations than in others. It will be a very interesting debate to see if the new scale will be adopted by other national weather services around the world considering the structural differences of home and buildings structures and materials used to build.

 

[Greg Stumpf]

Can anyone solve this doubt ? The damage descriptions considers the kind of structures and constructions that exist in the United States. Just one example. Here in South America, one of the most tornadic areas of the world, there are no mobile homes. Every country has its particular construction code and buildings and homes may be more as solid in some nations than in others. It will be a very interesting debate to see if the new scale will be adopted by other national weather services around the world considering the structural differences of home and buildings structures and materials used to build.

Most of us connected to the development of the EF scale understand that the damage indicators (DI) apply to mainly United States standard construction, and that new DIs for other types of construction, including European and other "stronger" residential home structures need to be added. That is one of the strengths of the new EF scale - expandability for new DIs.

 

[Alexandre Aguiar]

Dear Greg

Thank you so much for your answer. So, is it far to say that for now it is not wrong to still use the "old" Fujita Scale to estimate tornadic events outside the US ?

Alexandre

 

[Greg Stumpf]

So, is it far to say that for now it is not wrong to still use the "old" Fujita Scale to estimate tornadic events outside the US ?

Not really. The old Fujita Scale's primary damage indicator (DI) were single-family residential structures, with the same caveat - standard U. S. construction.

I would recommend that everyone adopts the EF-scale worldwide as soon as it is implemented in the U. S. (1 Feb 2007), and consider adding new DIs where appropriate and as soon as possible, including the residential "fortresses" I've seen in Europe.

 

[scott r currens]

The latest revision includes an EF5 rating for family residence damage indicator. I think Greg Stumpf posted about this in the past, but I remember hearing about it at November's SLS Conference as well. Read "Revision 2" (Oct. 10 2006) of the report at http://www.wind.ttu.edu/EFScale.pdf (the family residence DI is on page 25 of the PDF, or page A-2 of the report)...

EDIT: Actually, the expected wind speed for DoD 10 is 200mph, which is the upper-most bound of EF4, if I'm not mistaken. The range of windspeed, however, is 165-220mph, so an upward adjustment to the "expected" windspeed for DoD10 would bring it into the EF5 category. I think there have been modifications to other DIs and DoDs in the latest revision.

I noticed today that NWS Topeka and NWS Pleasent Hill have links to the original web site that caused me to start this thread. Does that mean they are using the wrong EF-scale?

 

[Jeff Snyder]

Scott,

You could email the webmaster. As far as I know, suspicion of EF4 and/or EF5 should lead to the dispatch of the QRT. The QRT should do the assessment for potential violent tornadoes, and they should definately know and have the latest revision of the EF-scale (namely, the inclusion of EF5 for DI2 -- one- and two-family residences).

 

[Evan Bookbinder]

Scott,

It would appear that SPC had the wrong links, so we definitely need to get ahold of them. Our website and Topeka's both reference the same site. On our survey of ern KS (I had the latest guide handy, so it's just the link that's bad, not our minds)

Evan

 

[Kevin Askew]

LOL I just dont like saying "EF" .... Kinda reminds me of old ef hutton commercials