This gives more credence to the claim that tornadoes, even ones that are genuinely below the violent threshold, have far stronger winds than thought.
Nice points - though is there more to this than is contained in that tweet? Because I can't see specific statements that you are making your numbered points against.
I think the windspeeds on the EF-SCALE are too low. I made my own and no I don't round up to the nearest 5 or 10.
From what I've read, the pressure drop in very strong tornadoes is 100 mbar, maybe up to 200 and occurs over a sufficient time period and houses are sufficiently porous that it doesn't really do anything.
Kind of like how there can be more 165 mph EF3'S than 166 mph EF4'S just like you say 200 mph EF4'S and not 201 mph EF5'S. When I ask other NWS offices about this you never get an answer back. I don't care what people think but I am very suspicious they are hiding something.
We just have DOW7 right near the Greenfield when it did high end EF4 damage(some claim near or reached EF5 level) and they got as high as 290mph winds. We don't know it's a raw velocity or Vp and aspect ratio adjusted ratio.
One thing noted here is those cases seem to be surprisingly well accord with IF scale wind speed scale.
The winds in the Greensburg tornado were probably as high as 260 to 290 mph and it certainly did EF5 damage.
I see a simple google search would have saved me a wall of text. It seems crazy to me that homes are porous enough for that though, especially when a tornado could be approaching at 70 mph.
After years I've finally see someone said what always want to say and agree. It's been an idea in my mind for really long time.
The pressure gradient and net force thing could explain some inconsisteneny we see if we only use wind speed. One example is Bridge Creek and Mulhall. They basically had the same value on DOW3 near the same level while damage was such different. Also 13 El Reno type of tornado would very likely had stronger winds than Moore 2013 cause it had much more subvortex. With some subvortex traveling at 80m/s, it would be extremely hard for Moore 2013 type of tornado(lacking subvortex) to beat if we just talking about pure wind speed.
I suppose I just find it pretty hard to believe that the air within a house is capable of conforming to the atmosphere surrounding it purely from a pressure standpoint, especially when talking about tornadoes that reach forward translational speeds of over 50 mph. I would love to see papers or studies exploring this idea, that may be a major factor within the sledgehammer effect. I can definitely see it not being a factor in slow movers, but with fast violent monsters like Smithville/Hackleburg/Mayfield the wind/pressure gradient has to be unbelievably tight, winds can go from 30 mph to about 250 mph in roughly 15 seconds in those extreme tornadoes. If it isn’t the pressure, then what is that factor that could possibly come into play?
The best pressure measurement we have now was still Manchester SD 2003. The pressure dropped 100hpa in just 10s. So the wind just complete its acceleration in such short time. That tornado moved at 8.3m/s when approaching the probe which is only typical level in plain. For tornados much faster and stronger than Manchester like Smithville, I would expect a much shorter and stronger pressure fall and wind acceleration than that. I would be very surprise that kinda of pressure gradient and acceleration itself wouldnt attribute if not done the damage mostly.
That’s very interesting and only adds to my suspicion about winds being the only thing doing the damage. But again, it may not be the pressure, it could be something else entirely (which I sort of doubt, but it’s impossible to draw conclusions without studies being done on it.)
I can't remember the tornado, but there's a well-known pic of window curtains having been drawn through where the roof met the walls; hard to imagine them being blown through from the inside but easy to see that happening with a vacuum pulling them from the outside. IIRC, the measured pressure when winds blow down garage doors and over-pressure the house is 3psi- not much at all but combined with a strong pressure drop outside would be much stronger in effect. I don't think houses are so porous as to have much effect on the suddenness of the pressure change as a slowly applied 3psi would do nearly nothing. And while I'm not privy to the details of the Texas Tech wind testing procedures, I can't see how they could replicate the pressure drop at the core, but measuring the windspeed would be easy to do accurately since you're creating that wind. It's also one of the main reasons I am suspicious of the correlation between actual winds and either Fujita scale's estimation of them. We've seen enough low-level DOW measurements not aligning with the scale to know there's something more happening that we're missing.
I don't think they're trying to hide facts- it's simply that they have no plausible explanation which fits the observed facts, and therefore no way to justify their actions. They remain silent to hide their stupidity on this matter.
Just want to point out that with the structure intact, old homes are quite leaky while newer homes are far less so to gain efficiency in heating and cooling them. There are even cases where homes are so air-tight that the inhabitants became ill from a lack of fresh air and a device known as an "air exchanger" was needed to provide enough fresh air. Porosity varies but can be lower than you'd think.
That makes sense. Good to see the deep reasoning in this thread versus the usual nit-picking arguments which often occur with these discussions.
Like the original F-SCALE, Fujita used numbers that were rounded to the nearest 0 or 5. One thing I would like to say in regards is that on the F-SCALE is that 260 mph was the very last numberof F4 and 261 mph was the very first number for F5.
