Enhanced Fujita Scale upgrade

[Jeff Duda]

Just came across this: http://blog.ametsoc.org/news/new-standard-aims-to-improve-tornado-severe-wind-estimates/

Haven't really seen anything else on this issue, but it appears significant changes may be coming to the EF-scale in the near future.

 

[Rob H]

If you go to that link, and follow the link to the presentation, there are some cool slides available, like this one discussing mobile Doppler readings vs. observed measurements:

http://apps.weather.gov/efscale/documents/02032014/08-Burgess.pdf

 

[Jeff Snyder]

Just came across this: http://blog.ametsoc.org/news/new-standard-aims-to-improve-tornado-severe-wind-estimates/

Haven't really seen anything else on this issue, but it appears significant changes may be coming to the EF-scale in the near future.

Making an EF Scale standard is going to be a long process, but this is definitely a necessary step to provide flexibility to the EF Scale by allowing for the addition of new DIs and DoDs and modifying or eliminating existing DIs (e.g., there seems to be research to support the idea that the distinction between hardwood and softwood tree damage isn't necessary). This really doesn't have much to do with existing NWS policy regarding non-damage-based observations or estimates, though, since those decisions are beyond the scope and power of the EF Scale Stakeholders group. We'll likely eventually have some guidance not only on specific wind estimate methods (e.g., radar measurements, tree-fall patterns, automated/imagery-based damage assessment, etc.), but also good guidance on how to develop new estimates. It's going to be slow going getting this in place, though.

 

[Elaine Spencer]

IIRC the American Society of Civil Engineers are the group that surveyed the Joplin damage and concluded that it COULD all have been done by EF-4 or lower winds. This report was widely misinterpreted/headlined in the media as "Joplin wasn't really an EF-5." I suspect this has a lot to do with ASCE's interest in the topic.

 

[Greg Higgins]

ASCE made a major impact because, once again, they pointed out and documented that poor building codes and even worse construction techniques, was to blame for a lot of the damage.

 

[Jake Orosi]

IIRC the American Society of Civil Engineers are the group that surveyed the Joplin damage and concluded that it COULD all have been done by EF-4 or lower winds. This report was widely misinterpreted/headlined in the media as "Joplin wasn't really an EF-5." I suspect this has a lot to do with ASCE's interest in the topic.

An important consideration is, "why would this matter?" I think people attach too much significance to this number - everybody hangs upon it, everybody waits impatiently for the NOAA investigative team to report an EF number; and lesser numbers than the local population feel the tornado "deserves" are subject to criticism. As if calling the tornado an EF-4 is somehow deeming it "less worthy" of attention, or the victims less worthy of sympathy, or something else, than an EF-5 tornado would have been. I think the agencies involved in developing and using the EF scale should make a public outreach effort to educate the public about the purpose and utility of the scale and "depoliticize" its usage.

 

[Mike Tobin]

Jake I could not agree more.

 

[David E. Young]

To me, the only value in designating a tornado on a scale is for statistics / science. If at a later time, a researcher wants to go back and make some correlation between certain weather set-ups and the probability of a violent tornado, it would be nice to be able to correlate EF scale numbers with other elements of a weather system. Having the most accurate measurement as to the violence of a tornado would be helpful.

 

[calvinkaskey]

Joplin damage survey

Looking at thousands of damage photographs with trees and buildings it seems like tree damage very well could be the best way to determine wind speeds as they are hit much more frequently than buildings. I'm guessing that tree damage could be used to determine if the housing construction was subpar. Also cars take f-2 or higher winds to be overturned so we will see if there really is an unbiased look at the damage.

 

[calvinkaskey]

I'm guessing that tree damage could be used to determine if this is the case. Also cars take f-2 or higher winds to be overturned so we will see if there really is an unbiased look at the damage.

 

[calvinkaskey]

ASCE made a major impact because, once again, they pointed out and documented that poor building codes and even worse construction techniques, was to blame for a lot of the damage.

I didn't see any tree damage or car damage that makes me think this this is the case. I question that the original F scale was really flawed after Fujita spent his whole life studying damage and it was accepted for such a long time.

 

[Shawn Schuman]

There is work being done with regard to more detailed use of trees and other similar indicators, but the problem with them is that there are just so many variables. Each species of tree reacts differently - some lose their bark more readily than others, some are denuded easier, some are snapped off or uprooted more easily, etc. - and on top of that things such as soil condition, the health of the tree, the type and amount of debris loading that may have affected the tree, and about a thousand other things must be considered as well. In general you can assume that a tornado which causes extensive debarking/denuding is probably more violent than one that doesn't, but it's hard to be specific without detailed analysis.

 

[rdale]

I question that the original F scale was really flawed after Fujita spent his whole life studying damage and it was accepted for such a long time.

It was accepted because it was the only process widely available with some sort of science background. Remember he developed this in the 70s and it was unchanged since then. To think that science hadn't progressed in how we understand tornadoes and the damage they do is simply a case of not paying attention to the science.

 

[calvinkaskey]

Questions about ratings in New York and low pressure.

There is work being done with regard to more detailed use of trees and other similar indicators, but the problem with them is that there are just so many variables. Each species of tree reacts differently - some lose their bark more readily than others, some are denuded easier, some are snapped off or uprooted more easily, etc. - and on top of that things such as soil condition, the health of the tree, the type and amount of debris loading that may have affected the tree, and about a thousand other things must be considered as well. In general you can assume that a tornado which causes extensive debarking/denuding is probably more violent than one that doesn't, but it's hard to be specific without detailed analysis.

The pressure readings that I have seen with tornadoes are incredible. It would make me tend to also favor the old scale. Some of the tornado damage I have seen rated in New York seems very unreliable. A tornado rated an F-3 in the Binghamton area ( May 31, 1998) without widespread debris, only overturning one car, not denuding any trees and from just one house that was ripped cleanly. About the same day this year near Albany similar damage and rated F-3. One tornado ripped part of a roof off, imbedding wood into the ground deeply, blew out a window and cracked part of the "base" of the house only rated F-1.

 

[Shawn Schuman]

I live in BGM's CWA and am familiar with the 1998 tornado; while it was relatively weak over much of its path (and possibly not one continuous tornado at all), it did extensive damage (consistent with F3) to the home you're referring to in Deposit. I also remember seeing pretty significant tree damage near Rt. 8 and the Cannonsville Reservoir. My dad took me to see it several times since we only lived ~10 miles from there. The fact that the worst damage only occurred in a few isolated areas doesn't mean anything as far as the maximum rating is concerned.

As for the last part, everything you described sounds pretty well in line with what you'd expect from an EF1 rating depending on the construction quality of the home(s) in question.