May 24 Plains/MW Severe Threat

[shaggy]

One thing I forgot to mention about this tornado. A group of us went to a friend's house that evening that had an underground shelter. After the wives and 4 kids squeezed inside, I went outside to take a look at the storm as it was passing north. I heard what I thought was a continuous low thunder, lasting a couple of minutes at least. However, after talking to other people in the area, I believe I was actually hearing the tornado itself. The house we were at was at least 5 miles from the tornado. Very flat, few trees or structures between that house and the tornado. Do people here think it's possible to hear a tornado of that magnitude from 5 miles away?

I felt like a tiny speck on the ground seeing the inflow going into that storm. The entire atmosphere above me was flowing into that thing.

During the March 1984 carolina outbreak we had an F4 pass within 4-5 miles of my house. I was 9 at the time and I remember my parents freaking out when they went outside and could hear the tornado. So yes I believe it is certainly plausible that a tornadoes of such strong wind speeds can be heard for longer distances.

I also experienced this when I went through the eye of hurricane Bertha in 1996. As the eye was moving overhead we could start to hear the rumble of the winds coming on the back side for a solid 5+ minutes as the hurricane force winds were coming closer. It was just an ever growing loud rumble.

[Hoosier]

I was under the impression that it's rare to hear tornadoes at that distance. I guess there are multiple factors that go into it. Years ago I remember hearing the wind 2-3 minutes before an intense bow echo (trees were not moving at my location), but that would've only been a couple miles.

[jpeters3]

I know winds arent everything when determining the EF-rating. I think it is just an estimate to what type of damage may be expected in association with that wind speed. If you are talking windspeeds being estimated on radar of 280-320mph that is almost out of this world crazy. Do you know if any windspeeds were estimated on radar for the Tusacaloosa, Hackleburg, Smithville/Shotsville, Philadelphia, or Joplin tornadoes? I know that radar may clock higher windspeeds inside tornadoes even though they may not be required to cause that associated type of damage. Here was the estimated windspeed for each of them in association to the damage Tuscalossa(190mph), Hackleburg(210mph), Smithville/Shotsville(205mph), Philadelphia(205 mph), and Joplin(220-250mph). Also I will include the Greensburg and Parkesburg tornadoes which had estimated winds of about 205mph. Even if a few of them tornadoes in OK get upgraded to EF5 they will most likely have winds estimated between (200-220mph) in respect to the damage, although winds clocked may have been much higher.

where on earth are you coming up with half of these wind speed estimates?

[jpeters3]

This is not accurate, that's all I can say at this point.

There were no direct 10-m wind speeds from the may 3 tornado - the only measurement I am aware of is the 301+-17 by DOW, which was much higher within the funnel.

[hm8]

Forbes on the wind speeds...

Dr. Greg Forbes Somebody asked yesterday about the wind speed in the Joplin, MO tornado that was rated EF5. NWS now estimates 225-250 mph. I believe that this is the fastest estimate since the EF-Scale was introduced in 2007.

[huronicane]

There were no direct 10-m wind speeds from the may 3 tornado - the only measurement I am aware of is the 301+-17 by DOW, which was much higher within the funnel.

I think he was saying that in response to recorded Doppler winds in the El Reno tornado being in excess of that.

[gymengineer]

where on earth are you coming up with half of these wind speed estimates?

They're all from the NWS survey reports themselves.

[Stebo]

Do we really know though? Yeah, it's probably safe to assume that tornadoes don't produce 500 mph winds, but is something like 330 mph that far-fetched?

No of course not. Its more unbelievable that it could happen than that it did happen.

[jpeters3]

I think he was saying that in response to recorded Doppler winds in the El Reno tornado being in excess of that.

Ahhh, I see - well regardless, the 150 mph mesonet gust is pretty amazing.

They're all from the NWS survey reports themselves.

I think I misread the original post a bit. I don't think Springfield WFO mentioned a specific range like that though for Joplin... right now it's just listed as 200+. Where did you hear those numbers?

Edit: I just read the post about Forbes. My forum reading skills have clearly taken a dive over the past few days

[blackjack123]

where on earth are you coming up with half of these wind speed estimates?

That is what NWS rated the tornadoes based on the damage. Those were the assigned wind speeds given from NWS offices for them tornadoes.

[tornadotony]

Some random trivia as we await ratings from Norman. IF all three potentially EF5 tornadoes receive EF5 designation, then Oklahoma will join Indiana as the only state to be struck by 3 EF5 tornadoes on the same day, which occurred in Indiana on 4/3/74. Additionally, 5/24/11 would go down as only the third date in recorded history with three tornadoes receiving EF5 designation, the other two being 4/3/74 and 4/27/11.

[gkrangers]

This is not accurate, that's all I can say at this point.

Why so secretive? We're talking tornadoes, not national security.

[jpeters3]

That is what NWS rated the tornadoes based on the damage. Those were the assigned wind speeds given from NWS offices for them tornadoes.

yeah, that post was a product of me failing to read thoroughly, not you posting misinformation. My apologies.

[AtticaFanatica]

Why so secretive? We're talking tornadoes, not national security.

I think the parties involved prefer to make sure there are no issues before going "public" with anything about radar observations. Unfortunately, that tends to lead to rumors, which are often inaccurate.

[shaggy]

It amazes me how fast these storms last week intensified. We saw it with the Joplin tornado when it went from a small thin width tornado to a monster and in this video the oklahoma tornadoes sort of did the same thing.

[shaggy]

close call

[Ian]

It amazes me how fast these storms last week intensified. We saw it with the Joplin tornado when it went from a small thin width tornado to a monster and in this video the oklahoma tornadoes sort of did the same thing.

im sure a big part of it is the proliferation of video catching things not widely noticed prior. at some point almost every daylight tornado may be recorded.

[shaggy]

im sure a big part of it is the proliferation of video catching things not widely noticed prior. at some point almost every daylight tornado may be recorded.

Yeah I guess that makes sense. Now with the phones with video capacity we are seeing even more videos and people taking bigger risks and this will lead to previously unseen aspects of tornadoes.

This guy was 20 seconds away from getting hammered.

[Hoosier]

Some random trivia as we await ratings from Norman. IF all three potentially EF5 tornadoes receive EF5 designation, then Oklahoma will join Indiana as the only state to be struck by 3 EF5 tornadoes on the same day, which occurred in Indiana on 4/3/74. Additionally, 5/24/11 would go down as only the third date in recorded history with three tornadoes receiving EF5 designation, the other two being 4/3/74 and 4/27/11.

Didn't Alabama have 3 on 4/3/74? Are you using Grazulis ratings?

[blackjack123]

yeah, that post was a product of me failing to read thoroughly, not you posting misinformation. My apologies.

Thats ok it happens sometimes.

[downeastnc]

During the March 1984 carolina outbreak we had an F4 pass within 4-5 miles of my house. I was 9 at the time and I remember my parents freaking out when they went outside and could hear the tornado. So yes I believe it is certainly plausible that a tornadoes of such strong wind speeds can be heard for longer distances.

I also experienced this when I went through the eye of hurricane Bertha in 1996. As the eye was moving overhead we could start to hear the rumble of the winds coming on the back side for a solid 5+ minutes as the hurricane force winds were coming closer. It was just an ever growing loud rumble.

Actually it was more like 2-2.5 miles ( according to google earth ) as the crow flies from our house not 4-5 miles. Regardless the sound was very loud like a long rumble of thunder that lasted for quite awhile.

As for upgrades it seems like there should be more EF5's since it goes from 200 and up, basically every F4 in the past would today be a EF5 if they happened today, if March 28th 84 happened today NC would have had 2-3 EF5's.

Outbreaks like the Super Outbreak in 74 had 24 F4's which if added to the 5 F5's means had that happened today and the storms got the same ratings would have meant there were 30 EF5's in one outbreak.

[jpeters3]

Actually it was more like 2-2.5 miles ( according to google earth ) as the crow flies from our house not 4-5 miles. Regardless the sound was very loud like a long rumble of thunder that lasted for quite awhile.

As for upgrades it seems like there should be more EF5's since it goes from 200 and up, basically every F4 in the past would today be a EF5 if they happened today, if March 28th 84 happened today NC would have had 2-3 EF5's.

Outbreaks like the Super Outbreak in 74 had 24 F4's which if added to the 5 F5's means had that happened today and the storms got the same ratings would have meant there were 30 EF5's in one outbreak.

F4=EF4

F5=EF5

i.e. an F4 ten years ago would still be rated EF-4 today. If anything, damage assessment has become more stringent due to better awareness of the construction quality of a structure on the DOD.

[natecast]

F4=EF4

F5=EF5

i.e. an F4 ten years ago would still be rated EF-4 today. If anything, damage assessment has become more stringent due to better awareness of the construction quality of a structure on the DOD.

Exactly. The EF scale is a damage scale, not a wind speed scale. It still takes the same type of damage to rate a tornado an EF-5 as it used to be for an F-5.

[blackjack123]

Didn't Alabama have 3 on 4/3/74? Are you using Grazulis ratings?

How many F5 tornadoes were there that day? Some sources say 6 and others say 7. Even SPC lists 7 but I always thought it was 6.

[thewxmann]

How many F5 tornadoes were there that day? Some sources say 6 and others say 7. Even SPC lists 7 but I always thought it was 6.

Depends on if you consider Tanner #2 an F5.

[downeastnc]

Exactly. The EF scale is a damage scale, not a wind speed scale. It still takes the same type of damage to rate a tornado an EF-5 as it used to be for an F-5.

I understand that however in order for a tornado to get a F4 rating the damage had to be consistant with winds over 207 mph. Assuming that the damage surveys conducted in the past where accurate and all past F4's had winds over 200 mph wouldnt it figure that had they all happened with the new system they would have been EF5's. I guess my point is with the new system one would expect to see a lot more EF5's and they shouldnt be as rare as the older F5.

[natecast]

I understand that however in order for a tornado to get a F4 rating the damage had to be consistant with winds over 207 mph. Assuming that the damage surveys conducted in the past where accurate and all past F4's had winds over 200 mph wouldnt it figure that had they all happened with the new system they would have been EF5's. I guess my point is with the new system one would expect to see a lot more EF5's and they shouldnt be as rare as the older F5.

The winds estimated in older tornadoes using the F-scale where just that: estimates. Further reserach leading up to the EF-scale indicated winds did not have to be as strong as previously thought to generate the same type of damage. Sureyors first survey the damage, then estimate the wind speed from there, not vice-versa.

[jpeters3]

I understand that however in order for a tornado to get a F4 rating the damage had to be consistant with winds over 207 mph. Assuming that the damage surveys conducted in the past where accurate and all past F4's had winds over 200 mph wouldnt it figure that had they all happened with the new system they would have been EF5's. I guess my point is with the new system one would expect to see a lot more EF5's and they shouldnt be as rare as the older F5.

I could see how it would be confusing - confused the heck out of me when they introduced it. The point we are making is that prior wind speed estimates were too high - current ones for the EF scale are thought to be more accurate. In other words, a tornado rated to be F4 with estimated winds of 220 mph probably had winds closer to 170 mph.

[CUmet]

This may be of interest:

The weather service undertook a full day of storm surveys on Wednesday, mostly on the El Reno storm track. One of the participants came over to the HWT and gave us a briefing in the early afternoon. The damage pictures he showed were just phenomenal...I've never seen anything like it. Not even in the 3 May 1999 event. A large oil derrick, several stories tall and weighing millions of pounds, was knocked over and rolled several times; the workers sheltered in a small bunker that was strapped down with guy wires. One of the wires snapped, but the bunker survived. There were numerous examples of trees being debarked, grass being stripped from the soil, asphalt being stripped from roads, and well-constructed houses being swept completely clean off the foundation. He showed some pictures of mangled vehicles twisted together, some of which had been thrown large distances. An 18-wheeler was thrown 100 yards. A Ford Escalade (huge SUV) was thrown 900 yards. A compact car was found leaning against a tree with a 2x4 plank puncturing the floor of the car (it had come in through the window). If this damage isn't EF-5, I don't know what is. On Thursday night we went out for drinks with some people from OU, including a guy who had participated in the survey...he showed us a picture he had taken of a decapitated rabbit head lodged among debris in a debarked tree! Disturbing.

http://grubshanks.xa...tem/?ref=recent

[gymengineer]

I understand that however in order for a tornado to get a F4 rating the damage had to be consistant with winds over 207 mph. Assuming that the damage surveys conducted in the past where accurate and all past F4's had winds over 200 mph wouldnt it figure that had they all happened with the new system they would have been EF5's. I guess my point is with the new system one would expect to see a lot more EF5's and they shouldnt be as rare as the older F5.

I know two other posters tried to clear it up for you again above this post, but I just wanted to point out exactly where your confusion lies-- the bolded part. The surveyors surveyed the damage. They didn't measure the wind speeds. So where your assumption is wrong is "all past F4's had winds over 200 mph." They didn't... their wind speeds were overestimated because the Fujita scale had the "wrong" wind speeds matched up to each category. Maybe you're thinking of the Fujita scale like the Saffir Simpson scale, where the categories are determined by wind speeds. As others have explained, in the EF/Fujita scales, the damage is the determining factor for the rating.