Storm Australian Severe Weather Forum
Severe Weather Discussion => Tornado Alley Outbreaks and Severe Weather Worldwide => Topic started by: Jimmy Deguara on 16 May 2007, 10:14:25 AM
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Once again referring to Greensburg, it seems the EF-5 rating is being questioned. I won't mention by whom but it could be a due to politics be it funding requirements not sure. It is a shame if this is the case but where does one draw the line given everything is flattened and requires massive government funding to be re-built.
Anyway, what are others' thoughts about the damage they have seen. I never believed I saw any damage that matched EF-5 and was rather shocked when I heard it on the Weather Channel.
Regards,
Jimmy Deguara
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Remember that there were very few houses (or lack thereof) in Moore that represented F5 damage. It has been a while since I have looked at the Fujita scale and really have not sat down and looked at the actual 'enhancemements' (ie EF scale), although is it not the case that the most intense damage is considered (whether it is 1 well constructed house or 100)? By all accounts, the magnitude of rotation of the Greensburg storm was at the very top end of the scale -- it was a very, very intense supercell. The actual damage observed in Greensburg? -- I'll leave that to the experts (or local politicians!).
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Hi David,
The damage survey was also done by a reputable engineer who has done other surveys in the past including Moore. Another reputable chaser with sharp eyes for detail also suggests that the damage Moore was a somewhat more intense than in Geensburg. What readings were experienced I cannot suggest. Was it the shear size of the tornado being 1.7 miles wide as compared to half mile wide at Moore would perhaps represent different readings? Not sure.
We happen to see the damage from Moore on Tim Marshall's DVD and it was very intense in terms of the cars being toppled around and crushed. Apparently the reading may have been issued given a car was moved from its location Anyway, we will a little later - this person has to release a paper so it will be interesting professionally what evolves.
Coincidently, I went to an AMS (American Meteorological Society) meeting at Fort Worth NWS, The topic being presented was the new EF scale. The new scale in summary changes the winds speeds represented by the various damage scales. They wanted a better scale representive of the winds - the lower end were too low and the upper end winds were too high. The damage scale itself is the same so it fits with old data. There are other components whereby the steps used to determine the rating can be scrutined or checked to be more consistent but I think the summary above is sufficient for this discussion.
Regards,
Jimmy Deguara
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My 2c worth on the deabate about Tornado strength or intesity is this: I haven't seen real finger of God devestation since the infamous Jarrell Tornado., May 27 1997. That torndao actually scoured the ground of grass and it turned a Prime Mover into the most twisted piece of wrecked debri I have ever seen, it also stripped the skin from the carcasses of people and cows. Not to mention though that houses it destroyed were not "well constructed" brick or masonary homes, however it not only tore them completely from the foundations but it completely obliterated the debri leaving in some cases nothing at all! It was definately more savage then moore imo.
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Hi Jimmy,
yep I guess it does come down to a final objective assessment of the damage. Obviously there is no meaningul correlation between tornado width and strength - eg Hallam was also EF4. The thing is though, Greenburg is a two-and-a-dog hamlet - I'm not being disrespectful at all, but Moore is a fairly high-density urban area. You cannot compare the two based on apparent damage to vehicles as I would think there would be many more vehicles available as debris in an urban area. The Moore tornado was apparently 1 mile wide near Bridge Creek, just southwest of Moore. This was the other area of F5 damage. Bridge Creek is smaller than Greensburg and I dont recall seeing such obvious carnage as there was in Moore. Yes there were some cars that were twisted wrecks and buildings were completely flatened / debris removed, but in Moore there were twisted wrecks and God knows what else everywhere. So, it all comes back to the actual damage assessments in my oppinion.
yeah Jeff, Jarrell was huge. Perhaps the somewhat slower movement of the tornado meant that anything in the path really did get dusted up. It is impossible to say whether maximum windspeeds were greater than in Moore/Bridge Creek but I agree, that on the evidence available, it does seem to have obliterated structures like no other tornado has.
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Bridge Creek / Moore Tornado ( http://www.srh.noaa.gov/oun/storms/19990503/storma.php#9 )
"Bridge Creek
Two areas of F5 damage were observed in the Bridge Creek area. The first was in the Willow Lake Addition, a rural subdivision of mobile homes and some concrete slab homes in Bridge Creek, in far eastern Grady County. Two homes were completely swept from their concrete slabs, and about one dozen automobiles were carried about ¼ mile. All mobile homes in this area in the direct path of the tornado were obliterated, resulting in a high concentration of fatalities. Asphalt pavement about 1 inch thick was also peeled from a section of rural road EW125. The second area of F5 damage was observed about 1 mile west of the Grady/McClain County line and consisted of a cleanly swept slab home with foundation anchor bolts and another vehicle lofted ¼ mile. The maximum width of damage in Bridge Creek was estimated to be 1 mile. Approximately 200 mobile homes/houses were destroyed, and hundreds of other structures were damaged. The Ridgecrest Baptist Church in Bridge Creek was also destroyed. Twelve people died in Bridge Creek, nine in mobile homes. All fatalities and the majority of injuries were concentrated in the Willow Lake Addition, Southern Hills Addition, and Bridge Creek Estates, which consisted mostly of mobile homes. Compared to sections of Oklahoma and Cleveland Counties, which were also in the path of this tornado, eastern Grady County, including the Bridge Creek area, is rural and sparsely populated.
South Oklahoma City, northeast of Moore
The tornado then continued northeast and entered the southern portion of a sparsely populated industrial district. F4 damage continued through this area to near SE 89th St., the Cleveland/Oklahoma County border. Moving into Oklahoma County, the tornado curved northward, through the remaining industrial district north of Interstate 240, where 2 businesses were destroyed. This damage was rated F4. Two people were also killed at a trucking company near the intersection of S. Bryant Ave. and Interstate 240. A freight car, with an approximate weight of 18 tons, was picked up intermittently and blown ¾ mile across an open field. The body of the freight car was deposited southeast of the intersection of S. Sunnylane Rd. and SE 59th. Gouge marks were observed in the field every 50 to 100 yards, suggesting the freight car had been airborne for at least a short distance. While tornado A9 was moving through southeast Oklahoma City, another tornado (A11) touched down briefly near the intersection of SE 80th and Sooner Rd. (Oklahoma County). Tornado A9 then entered residential neighborhoods between SE 59th and SE 44th, where a woman was killed in her house.
Midwest City and the storm's demise
Tornado A9 then crossed 29th St. into Midwest City (Oklahoma County), destroying 1 building in the Boeing Complex and damaging 2 others. Widespread F3/F4 damage continued as the tornado moved across Interstate 40, affecting a large business district. Approximately 800 vehicles were damaged at Hudiburg Auto Group, located just south of Interstate 40. Hundreds of the vehicles were moved from their original location, and dozens of vehicles were picked up and tossed northward across Interstate 40 into several motels, a distance of approximately 0.2 miles. Numerous motels and other businesses including Hampton Inn, Comfort Inn, Inn Suites, Clarion Inn, Cracker Barrel, and portions of Rose State College, were destroyed. Some of the damage through this area was rated high F4, however low F5 was considered. The tornado then continued into another residential area between SE 15th and Reno Ave., where 3 fatalities occurred. High F4 damage was inflicted to 4 homes in this area. Two of these homes were located between SE 12th and SE 11th, near Buena Vista, and the other 2 homes were located on Will Rogers Rd., just south of SE 15th. Damage then diminished rapidly to F0/F1 as the tornado crossed Reno Ave. The tornado dissipated 3 blocks north of Reno Ave., between Sooner Rd. and Air Depot Blvd.
Summary
The Oklahoma State Department of Health in Oklahoma City recorded 36 direct fatalities. In addition, 5 people died of illness or accident during or shortly after the tornado, and were not considered in the direct fatality total. The number of injuries was estimated at 583, based on numbers provided from the Department of Health, which were then adjusted to account for people assumed to be unaccounted for. Injuries which resulted from removing debris, conducting search and rescue efforts, and taking shelter from the tornado, were not considered in the injury total. An estimated 1,800 homes were destroyed, and 2,500 homes were damaged, resulting in approximately $1 billion in damage."
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This is a great picture of the Greensburg tornado for before and after comparison if you haven't all already seen it. I won't make any judgment on the EF rating.
(http://i27.photobucket.com/albums/c172/enak12/Greensburg_KS_Before_and_After.jpg)
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The majority of homes damaged/destroyed in Greensburg were built before 1980...the construction was mostly high quality....several homes that were completely destroyed were built before 1930 when hardwood was used for structural framing....I have seen several homes in the past that had been built before 1930 that were "SKINNED" by F-3 damage on the old scale (157-206 mph)but the roof and wall structures remained intact...the parameters for the new EF scale were exceeded in several areas....the quote is "...If any or all of the damage is consistant with EF-5 damage then the entire damage path is considered EF-5 damage"....Just my 2 cents....
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The damage scale should really reflect the wind strengths of the original work by fujita.(By which this tornado was an F4).
I'm not sure how you arrive at this conclusion John - EF5 is not based on what we see from above or in photographs, but through intensive investigation of the damage by structural engineers. There must have been some damage in Greensburg, presumably a clean foundation where a house once stood, in order for that EF5 classification to have been given in the first place. Any subsequent questioning of this must be related to the state of that house prior to the tornado,,,, or something else. In the case of the Moore tornado, there was very little F5 damage either really. That said, perhaps Moore was a more 'violent', violent tornado, it is impossible to say.
Those images above are sobering to say the least.
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The damage HERE (http://www.srh.noaa.gov/oun/storms/19990503/) at Moore was particulary severe and was classed as F5.
And here is a pic of the Moore tornado.
(http://www.met.utah.edu/jimsteen/ams/quiz/quizpics/q2.jpg)
A quote from Sam Baricklow about the Jarrel F5 Tornado.
The amount of pavement removed by the tornado was amazing. The Jarrell tornado removed more asphalt pavement than the Dimmit, Texas tornado of June 1995.
Cars were even obliterated in Jarrel. Check out this pic.
(http://www.k5kj.net/jer14.JPG)
Jarrel tornado right before it became a Barrel/Wedge
(http://home.austin.rr.com/candylind/caching/deadmanwalking.jpg)
I think all three are obviously violent tornadoes, no doubt but as for ratings that has to be left for the experts. But I wonder how it compares to Andover in 1991?
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Hence from damage estimates we know that we likely have a tornado in the order of F4.
What do you mean "we" John? As far as I know a NWS damage assessment rated this tornado as EF5. If there was one single point of EF5 damage then it was EF5. Unless you have been through all the damage with a fine-toothed comb you are drawing a very long bow as to be so confident that is was not. Furthermore, your comparison to Moore is no grounds on which to conclude that this tornado was not EF5 . Accordingly, and based on what Jimmy wrote initially, the question is what/if any factors may have compromised the damage assessment. If this is found to be the case the tornado will no doubt be downgraded. I certainly wont be making the call from my armchair!
Hence from damage estimates we know that we likely have a tornado in the order of F4.
Again no you do not! You have not scrutinised the damage in any detail - you are simply comparing what you see in photos to a likely high end-F5 event in an urban area (Moore). The Moore tornado swallowed up a very large car yard of course there were more mangled cars. Of course there was more debris in the funnel (i would say) to act as a wrecking ball. Nevertheless, this Greensburg storm only had to produce spots of EF5 damage to be given that rating and that seems to be the case for the moment.
When all is said and done the Fujita Scale is a damage assessment scale, not a measure of a tornado's maximum intensity. Now, given that Greensburg is but a few miles north-south and given that this tornado died just north of town it did not have a great opportunity to produce EF5 damage really. You see, this is what interests me -- how intense do these beasts get...what are the limits? I don't care what EF rating is given to this storm in fact I'd rather them all be EF1! But which storm had the more intense circulation and tornado -- both of these storms are of an intensity seldom seen.
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That tornado is a beast Jeff - I think you'll find that is how it was as it approached Bridge Creek. The funnel was more slender (lets say a large stovepipe) as it approached Moore.
What amazed me with the Andover tornado was the intensity of rotation - I guess everyone has seen the video on Tornado Video Classics. In fact that might be the tornado where they commented on suction vortices being visible.
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I know we are going off topic, but here is some video of the Andover tornado. This always blows me away - check out that rotation...
http://www.youtube.com/watch?v=BAmKvxIEY20
Jarrell - not the best footage http://www.youtube.com/watch?v=k-K-bj8YhiQ
Oklahoma City - http://www.youtube.com/watch?v=4pbqGsS5iB4&mode=related&search=
red rock Oklahoma http://www.youtube.com/watch?v=AvMMcmtNUf8
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I agree that the Moore tornado was very likely a stronger tornado. I havn't studied the EF scale but maybe the Greensburg tornado gets its 5 rating due to the width of the destruction.
We passed through Greensburg area yesterday on our way south. While we weren't permitted to enter the town we did get to the edge of town where EF4 damage started.
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Steven,
The width of the damage path certainly was mentioned as a probable factor towards achieving EF-5 rating.
John, I don't have sufficient time to respond in depth to your points above (by the way please do not try clarifying points that should have been clarified and clearly discuss the topic).
The main aims in developing the EF-scale from the old scale was:
- to provide a scale that is consistent in terms of damage as the old scale
- to provide better estimates of wind strengths - that with better understanding of wind dynamics were proven to show lower ratings has winds too low and upper ratings had winds too high
- to provide more reliable techniques and an array of checks that enhance and hopefully provide more accurate wind estimates within the rating
So really EF-5 and F5 should be the same damage. The main point in discussion here (and hopefully to remain here) was that should funding /politics influence decisions if this was the case. To clarify even further, was the rating reasonable anyway - which is what is being discussed above? Perhaps it was close to EF-5 and pushed over the line for whatever reason?
Regards,
Jimmy Deguara
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I request that you back up your assertion that a a comparison to a supposedly similar strength(EF5) tornado is not valid? In my view while all tornadoes are different, it is likely that they contain consistent elements with respect to damage elements, hence on this point I justify my comparison with Moore.
Hi John - good post! We may be talking a slightly different language here. IMO, a comparison based on photos as available on the web - which is all we can do here is not valid for discerning tornado intensity. You commented yourself that Jarrell damage was on a different level. My point exactly - one cannot use photographic evidence of Jarrell as a standard by which to compare all other EF5 tornadoes. I have never suggested that Greenburg (or Moore) was the more intense tornado - simply whether or not Greensburg is EF5 or EF4. One EF5 tornado might clear the foundation of a complete row of houses (or whatever the criteria are with the new scale). Another EF5 might only clear the foundation of one house. The foundation of at least one house must have been swept clean in Greensburg for that rating to have been given (it seems you cannot find evidence of Ef5 damage from the web, hence your reason for EF4!). This is irrespective of whether Moore drilled a hole 1 mile deep into the ground and struck oil! Both are still EF5 despite photographic evidence suggesting one being more intense than the other based on the 'impressiveness' of damage. Do you understand my point?
From the evidence I have seen, Greensburg has set the upper limits of low-level mesocyclone intensity in recent years. This was a cyclic storm and different to Moore which was in a remarkably steady state by all accounts. We did not have all the GrLevel3 data around in 1999 either so we cannot say which storm had the 'Moore' intense rotational velocity (sorry, could not help myself). It would have been fantastic if a DoW was taking measurements of the Kansas tornadoes to compare with the 319mph +/- velocities recorded in Moore.
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Here's my 3 cents worth.
Does it really matter how close this tornado was to EF5 scale? In reality when i look at Greensburg which was 95% flattened, I don't really care if it was 3mph short of an EF5 'damage' scale. What constitutes an EF5 event that satisfies everyone? The town ground down to dirt? There were cars wrecked and flung around, there were structures that were obliterated that were'nt in the 'ground zero' section of the funnel.
There are reported cases of F0 tornadoes having the same damage path as an F4 purely on the assessment of the engineers who viewed the damage scenes and reports on F4 wedges having the comparible damage to an F2. Just because there were not particular items that were obliterated in relation to damage to Moore, Jarrell what does that matter? This storm was very vicious in its structure as we've seen also that it produced so many tornadoes from one storm system proved that. (even another EF2 was sighted heading for the town but lifted after the EF5 went through Greensburg!)
It must be remembered that the perameters set by these scientists for the F scale or the new EF damage scale have not been proven scientficially at all. The margins they use are 'a guide' to damage assessment dependant on what structures are destroyed. Does a trailer park obliterated off the face of the planet and vegetation stripped constitute and EF4 even though sightings of the funnel were of a marginally wide stove pipe for example?.
From the city before and after satellite pics would you rate the damage as high EF4 or low EF5? Jeepers, the wind perameters for both are negotiable. Surely it really doesn't matter only perhaps for the record books - but doesn't 95% of the observers say it was an EF5? Don't the scientific results, observations from the NWS agree on the wind profiles etcetera?
How can we ever determine EF5 damage if we dissect how many leaves were left on a tree or how many vehicles resemble rubbish bins? Greensburg's water tower was totally destroyed and that thing is not a small, light landmark!!!
For my 3 cents if the thing was 3mph slower in wind speed to rate an EF5 so what. Those damage ratings are variable - that's why they restructured the Fujita scale and no doubt will do so again with the EF version. Otherwise they would not have adjusted it at all if those perameters were gospell.
Mike
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So sorry if i misread some parts, was not stepping on toes at all! I see now. Well in that case there definitely is a course for comment!
I did not know that there was a 'case' for more funding. I would have presumed that whatever relief would come it would be 'across the board' given the damage. (destroyed or damaged - if my home was wiped of it's foundations I'd call that destroyed and 'beyond repair' really is not 'damaged' is it. 'Damage' really is a bit ambiguous when your lounge room is next door!)
Why or who on earth in the USA is quibbling about how much it takes to rebuild the poor town? Oh dear, i can see this is going to be another South Carolina without even to this day the government doing what it should to get the place cleaned up.
I take it all onboard and have nothing else to say! You'll forgive me as I know nothing about the claim for extra funding - more to my fault guys sorry!
Mike
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Bang on David, its good we are starting to talk on the same wavelength.
Yep John, it's clear that there were probably only a few spots of EF5 damage in Greensburg (ie based on the damage assessment that resulted in the rating). I'd say there must be some uncertainty with respect to those spots of damage and this has resulted in some questioning the initial rating. Obviously we are dealing with a spectrum of events - this tornado would probably be at the low-end EF5 (or EF4 depending on how flawed the assessment was). All this notwithstanding, boy, what a scary storm - some are suggesting the tornado that developed north of town was possibly more massive (as in width)!
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John,
Given the country the other tornado moved over I would not be surprised if the vortex was of a similar strength, but did not have a chance to do damage like that of Greensburg, and by the time it did the storm had weakened somewhat.
Although these are possibly the two main tornadoes it produced of such massive size, please do not think it had weakened. I think to produce two massive wedges is a thing in itself. The storm went on to produce multiple touchdowns with significant tornadoes possibly over a few hours based on its warnings though I will await the final assessment. Definitely by midnight, the storm was a stock standard tornado producer with not so extreme velocities.
I agree with David the second tornado produced a wider path.
(http://www.crh.noaa.gov/Image/ddc/GreensburgTornado/Kiowa%20county.gif) Please note these are county based assessment ie Kiowa County. Other assessments may be made by separate NWS offices or other teams.
Another interesting point made by analyses of radar is that the Greensburg tornado may have veered and come back into the eastern side of town and then merged with the second violent tornado.
Regards,
Jimmy Deguara
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Thanks for the link to those photos John. They are truly amazing photos - regardless of them being sold to the public or whatever - i agree that they are immensly useful in assessing damage. I particularly liked the one with the young girl on the swing amongst the carnage - innocence in the face of diversity. Wonderful stuff.
If the difference between EF4 and EF5 damage is a few extra branches snapped off then from viewing those photos really justifies whatever relief funds are needed. I've never seen anything like it - thankfully and surely these images must lay to rest that this tornado was just inexplicably monstrous whatever the argument is about relief funding - I just can't see the point in it looking at the damage!
Mike
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A friend of mine, who was riding with Jimmy on the night of this tornado, suggested to me that this tornado changed his whole view on storm chasing. Now, talking deliberately around Jimmy, since he would have his own perspective given that these guys saw the tornado, he described seeing the massive tornado (relying on lightning illumination, remember) and, soon after on approach to Greensburg, he described the intense pungent smell of gas, the continual moan of sirens (as in emergency vehicles not tornado sirens), damage, and a overwhelming sense of catastrophe on a scale which he had never experienced (and few people would experience). It was very fortunate that the second massive tornado did not hit any major towns.
Anyway, w/r to the tornado track above, note the 2nd major tornado very rapidly becoming VERY large - what a dangerous situation for spotters or reckless and / or inexperienced storm chasers. I would not want to be close to that first tornado, but if you were east of town you would have been in for a nasty shock as tornado 1 slid by northwards and a few miles to your west.
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Also on the map, you can note the tornado track curling back to the left during its weakening and final demise, indicative of the mesocyclone occlusion (Also obvious on May 12, 2004 Jimmy - gosh I feel like I am liivng in the past after looking at tomorrow's convective outlook haha). Also, note how the 2nd tornado track assumes more of a path towards the right while growing very wide, possibly reflecting a further right deviation in the track of the mesocyclone (right move) as it became more and more intense and the vertical pressure pertubation was enhanced. No doubt, the mesocyclone was exceptionally intense during this second tornado.
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My meteorologist chaser friend who lives in Oklahoma said to me that this tornado was the most awe inspiring yet most shocking thing he had seen in 6 years of chasing tornadoes. He had never, ever seen anything so ruthless - even from the Moore OK outbreak - the meso and speed of rotation was just unearthly. These events apparently coincide with the La Ninya every 10 years or so with uncanny regularity. Almost all of the outbreaks have had similar weather patterns and just as many supercells spawning multiple tornadoes. Truly why we are so interested in severe weather. So many questions and not enough answers from Mother Nature!
Mike
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Here's a photo of the Jarrell tornado just prior to it absolutely destroying the Double Creek housing sub-division near Jarrell http://www.nationalgeographic.com/ngm/9807/popup7.html
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Love the shot, David. I've done some research on the thing but never really saw a decent photo of it. I have a fellow workmate from western Texas. We were talking about tornadoes and he mentioned the Jarrell tornado. He was living close to the town during that time. His recollections of seeing the thing had a fairly negative impact on him psychologically. He's seen his factory wall peeled off like a sardine can from an F2 and seeing the Jarrell tornado still has an affect on him. He steers clear of any large hailstone producing supercells because he's fully aware that there may be a tornado around at any time.
I think every one including the meteorologists at the NWS are grateful also to the chasers that film and give reports - it's this kind of gratitude that makes what we do even more important to the whole spectrum of storm observation.
Mike
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Such good posts. Sometimes we get complacent about severe weather and as most of us do at times when there's not much intense events happening here or abroad. When they do happen it really gets the minds clicking over and reflecting back on past events and comparing them.
It proves beyond a doubt that these significant storms are just so complex and not always 'text book' after all. Sure they have all the characteristics etc, but as they have proved these supercells are a scientists/meteorologists dream when they happen. So much information gathered from start to finish and added to that the storm reports from chasers doing the right thing and takng notes of specific things about the tornadoes, rotation, structure and the like.
Fortunately technology makes it easier, but there's nothing like the human element to document footage so that the experts can review and enhance everyone's knowledge.
Who knows, they might even reclassify these 'rare' supercells to another level because of the information. Instead of your classic, LP and HP they might even prefix it something else!
Never ceases to amaze me that even the experts say that tornadoes are 'rare' with supercells - which is true to some extent as not all produce them - but having over 200+ in most seasons makes you wonder if they're not that rare at all!
Mike
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Yes sorry, John. I meant 'localised' tornadoes in one particular area. I understand there's that many just about every year. My train of thought was on the spate of current events. My fault! :)
Mike
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Hi,
Just in connection with this discussion, I have pictures of Greesnburg taken during our brief survey (http://www.australiasevereweather.com/forum/index.php?topic=443.msg3367#msg3367) at the following link:
http://www.australiasevereweather.com/forum/index.php?topic=443.msg3367#msg3367
Regards,
Jimmy Deguara
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In reference to the image posted by enak: i would very much like to see an image of the roadway two streets to the left of the main N-S street. It looks quite possible at that location that we have asphalt ripped up(at least partially) and if that is the case It would be there that i would be looking for some tracer of EF5 damage.
Hi John, just in relation to your comment about possible asphalt ripped up - what draws you to that possibility? Is it just the darkened colouration in the image at that location? I must say I spent 2hrs slowly driving most of the streets in Greensburg (yes I was Jimmy's chaffeur for the day) and saw no asphalt damage. Just curious to know if you have heard more?
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Hey all,
Well done on the great photos for Greensburg and other Tornadoes. I was also in USA chasing from May 12th until May 19th, unfortunately it was the week where not many storms formed, let alone Tornadoes.
One of our drivers John took these amazing photos the week after our tour,
http://www.nc911.com/Misc-Photos/storm_chasing_2007_greenburg,ks.htm, one of their guides was a TV Media Reporter, they were allowed into Greensburg for photos. What a devastating site to see, to see these photos, really shows the enormous power a EF4 or EF5 does have. From the people I have talked to in relation to this, I do believe its a EF5. During our chase, saw many towns affected by many other smaller EF3 Tornadoes, even these caused magnificent damage to structures.
Greensburg, nothing left to salvage. http://www.kansas.com/626/ Here are some other photos and reports of Greensburg.
I look forward to seeing Greensburg rebuilt in the near future.
Thanks
David
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Certainly some thought provoking images David. The raccoon also got my attention! The great thing about towns like these after major disasters is that they pull together and become even stronger community wise. Adversity brings out the best in people, especially terrible destruction such as what they encountered.
It will be most interesting to read all the conference/data reports of this event in the months ahead that the NWS, NOAA and experts alike will be compiling. EF5's are rare and systems like these are rarer.
I for one will be enthralled by the results and reports when they come out. thanks for posting the pics, certainly gives a scope to the damage.
Mike
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Hi David Carroll,
...What a devastating site to see, to see these photos, really shows the enormous power a EF4 or EF5 does have. From the people I have talked to in relation to this, I do believe its a EF5. During our chase, saw many towns affected by many other smaller EF3 Tornadoes, even these caused magnificent damage to structures....
Although I respect your point of view, the statement above if I understand it correctly seems almost contradictory. Also please tell us who you talked to about this that made you arrive at this conculsion. Further, you supply images from the media person - which of these perhaps convince you of EF-5 damage?
The EF-5 rating was derived using 3 points of damage within the town. One of these points that still remained was also used by another experienced assessor of damage and this person only sees EF-4 damage from the same assessment. For each point that makes me suggest an EF-5 damage factor, I saw other adjacent damage that makes me rethink lower.
Another thought crossed my mind: could the massive amount of debri carried with the tornado being so large have created 'impact' of incredible damage suggestive of higher damage usually associated with EF-5 when perhaps there may have been EF-4 damage/wind scale?
Getting back to the damage of power poles - most were leaning over but not snapped - even within the town. In the tornado that hit White Deer 29th May 2001, all power poles were snapped bar 1. Of course one can correctly argue the strength of the poles but really would not an EF-5 rated tornado have snapped power poles?
I guess I am not an expert but the damage simply did not add to what I had percieved to be EF-5 rating from descriptions such as those in May 3 1999 and Jarrell, Texas in 1997. What David Croan may be saying that there may have been multivorticies that could have created regions of locally EF-5 'maximum rating' (please correct me of I am wrong in my assumption David).
Regardless of the arguments in this debate, the damage is of mass scale I personally had not observed.
Regards,
Jimmy Deguara
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I think re the damage is something no-one can strike out as cut and dry. There are so many factors that scientists and meteorologists do not not know about wind factors in and around these storms simply because assessing damage from tornadoes has not been proven as 'a matter of fact' - it's all theoretical based on wind, debris, structures and the like. Smaller EF2 tornadoes have been 'assessed' as having EF4 damage simply because of the structures it has hit in its path and likewise EF4 tornadoes have done damage similar to lower rated tornadoes.
I think David was just expressing the view that from what he's seen and likewise yourself Jimmy, that we're not experts and even the experts rated it as high EF4 or low EF5 (if there is such a thing!).
I did not read his comments as contradictory at all - he mentioned either EF4 or 5, that's not contradictory, that's a viewpoint of what he has seen personally.
It gets back to the same question of relevance, is it EF4 or 5 damage - nobody knows, that's why the scale is set the way it is, it covers a range between these two. You answered his comment when you mentioned the amount of debris carried by the tornado may have caused EF5 damage - that may well be the case - if the tornado was on the ground for so long who knows what carnage was arond the vortex area - it would be agreeable to say that the more debris in the area most likely would have caused considerably more damage.
You could ask all the residents of Greensburg what they thought and you'd get mixed answers. Truth is we'll have to wait and see what the reports say on the event, but it's important to understand that just because residents say it was EF5 or other experts say EF5 or EF4 is irrelevant so far because no-one has the answer.
Mike
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Mike,
Rather than get off topic, read carefully what I have suggested as being 'almost' contradictory and don't assume what comments I am referring in his statement:
From the people I have talked to in relation to this, I do believe its a EF5. During our chase, saw many towns affected by many other smaller EF3 Tornadoes, even these caused magnificent damage to structures....
Further, Mike I think you will find that scientists have developed this lastest Enhanced Fujita Scale it being far more thorough. Mike in your generalised assessment of my post, you incorrectly quoted what I was alerting to. So perhaps if I was not clear, I will perhaps elaborate on my question: is it possible that the amount of debri carried around may have caused EF-5 damage despite perhaps the wind strengths causing EF-4 damage?
I await comments from David...
Regards,
Jimmy Deguara
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Jimmy,
Im far from an expert in relation to others on this forum. Mike is correct, i was mainly providing my opinion just on many other experts I have talked with. I have to say, they also have their opinion on whether it was a EF4 or EF5. This has opened my eyes to what one can expect when chasing storms of this magnitude.
The photos provided were of a driver also a photographer, not from a media person. John sent me these photos after the interest I showed, considering we never got to visit Greensburg.
Its just such a shame so many people had to lose their lives.
http://www.spc.noaa.gov/climo/reports/070504_rpts.html - This report says it all.
Dave
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The new EF scale just expands the wind speed perametres from the old one. And as David said it's just an opinion of what 'he saw' - not what he believes whole heartedly without expert qualifications to which none of us have in this determining this damage.
Mike
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David,
Fair enough - thanks for elaborating.
Mike said..The new EF scale just expands the wind speed perametres from the old one.
Mike, this is only one of the enhancements: there are others that may have been mentioned earlier.
Regards,
Jimmy Deguara
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:) Healthy discusssion and debate is what it's all about!
The EF scale does use 'wind speed' as set out by met people and wind engineers as they condensed the gusts somewhat and yes, have used the following also to compliment the scale.
The EF scale still is a set of wind estimates (not measurements) based on damage. It uses three second gusts estimated at the point of damage based on a judgement of 8 levels of damage to the 28 indicator list. The 3 second gust is not the same wind as in the standard surface observation. Standard measurements are taken by weather stations in open exposures using a directly measured one minute speed.
Reports were of wind speeds of 205mph which would rate it EF5, but what rating would they give it if it hit the same place last year? They would have rated it an F3 or F4 depending on the fastest 1/4 mile speed or the 3 second gust!
Mike
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Reports were of wind speeds of 205mph which would rate it EF5, but what rating would they give it if it hit the same place last year? They would have rated it an F3 or F4 depending on the fastest 1/4 mile speed or the 3 second gust!
Mike
Are you sure about that Mike?
The important thing here is that the emphasis is on damage, not wind strength. The 'windspeed' is simply an inference based on damage. They would have rated Greensburg v2006 based on a damage assessment, from which an F rating would be assigned ( I would say F5 based on cleared foundation subject to this thread's raison de etre). From the F rating, one could infer wind speeds according to the F-scale only. As it is, it was rated EF5, implying wind speeds greater than 200mph under the EF scale, but that's all. You cannot used wind speeds inferred by an EF rating to slot it into the F scale to determine an F rating.
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I guess I am not an expert but the damage simply did not add to what I had percieved to be EF-5 rating from descriptions such as those in May 3 1999 and Jarrell, Texas in 1997. What David Croan may be saying that there may have been multivorticies that could have created regions of locally EF-5 'maximum rating' (please correct me of I am wrong in my assumption David).
Hi Jimmy. Yes, suction vortices are one possibility for areas of locally enhanced damage. The EF (or F) scale does not consider how widespread the damage is in assigning an rating, but simply whether or not such damage exists and is attributable to the tornado. It does appear that, as far as Greensburg goes, the damage was not as 'complete' as Moore -- I know this is based on the opinions of damage assessors that you are in contact with who have observed both damage tracks. That's fairly compelling evidence I think. Nonetheless, this was a big tornado and will go down in history as the first EF5.
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Oops, sorry David forgot the 'E' in front of the latter part of my reply referring to 'F' ratings - my mistake, so your last part of sentence won't refer to that Allengans contraria non est audiendus Back at you!
I'm content with the views anyway posted here. I wasn't trying to add inferences to the F rating as I know it's not to be used now - and I'm aware that damage for EF4 and higher are rated on damage to well well-built constructions that are destroyed - but this argument will go on forever without a definitive answer. We can speculate, assess and conclude but in the end nobody knows how powerful these things are and that's why the science continues.
Mike :)
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Hi John,
In my view on the old scale it would barely rate F4, but thats my considered opinion.
Can you elaborate on this comment? So what does it rate in your books on the EF scale? Sorry to cover old territory but this quote puzzles me somewhat.
David, yes I am thinking of the sub-vorticies as perhaps some explanation of possible more intense damage locally. What are your comments regarding the possiblility of large masses of debri being carried around creating perhaps more damage as it may seem? I note on a documentary - take what one wants from it but known research experts were commenting about the possibility that the 1997 Jarrell accummulating appreciative volumes of dust and debri causing perhaps more intense damage than one would have anticipated. I realise this is only a generalised depiction of thsie statements but it is food for thought.
Regards,
Jimmy Deguara
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Hi John,
No what I am inferring is that I thought that the new EF scale keeps the damage consistent between both scales and adjusts the winds based on current knowledge.
Also, I note Brad had asked for further explanations and also you had drawn attention to ripped asphalt - thence possible EF-5.
In reference to the image posted by enak: i would very much like to see an image of the roadway two streets to the left of the main N-S street. It looks quite possible at that location that we have asphalt ripped up(at least partially) and if that is the case It would be there that i would be looking for some tracer of EF5 damage.
Any comments here?
Regards,
Jimmy Deguara
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Yes, It's Latin in both. Thought he was trying to out-gun me.
The Jarrell rating was F5.
Is John saying that they wouldn't have or would have rated it F5 if it was not for the photographic/public evidence that came from Greensburg? ( per John's sentence -: Jarrel wouldve been rated an EF5 and but for imagery of the event people would liken it to greensburg
They're not going to reclassify events pre-2007 to the new Ef scale,they've already rated Jarrell.
Does anyone have info on re this: Jarrell's F5 tornado at its beginning caused crop dirt to be ripped out to a depth of 50cm (20 in), so was there evidence of anything similar in Greensburg?
Edit: 8 in changed to 20 in
What the governing authorities have to clarify is how far does 'Devastating damage' for EF4 and 'Incredible damage' for EF5 go in order to define each? From what I've seen from Jarrell and Greensburg photos there's not a lot to question re extent of damage. By reading both the table of contents that cover EF4 and EF5 effects - just about everything (damage wise) that happened in Jarrell was mirrored in Greensburg.
Mike
With the wind being gauged at 205 for Greensburg it's an EF4 - but like we've all said all the way through the thread - there are areas which sustained damage caused by debris that reflected EF5 scale characteristics. We can only go by what the authorities tell us and take it as face value.
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This thread I think now is becoming clogged with various opinions and in some cases conflicting information that for any reader may become confusing - I guess it could then detract from the original topic and the original debate.
Thanks for all the worthy discussion - I think I will have this closed with perhaps permission from any member with anything new updated information related to the topic such as links to reports etc to be posted by the moderators.
Regards,
Jimmy Deguara