The Hurricane list is out - how do you prepare for one outside the "zone?"

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dpb wrote:

Oh, BTW...don't think that the combine "flew" -- it mostly rolled it like a not-so-round bowling ball. Still I guesstimated based on weight and surface area center-of-gravity it took well over 200 mph winds to tip it and get it going initially. It wasn't possible because of the debris field left in town from all the destroyed houses, trees, etc., to see a damage track it left except for a good gouge in the asphalt in the dealer drive from whence it left, but out of town through the fields it was pretty clear damage track that traced its progress...
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I've heard many descriptions of close encounters. Two that stuck in my mind were "It looked like God was hungry and was sucking everything in sight up through a straw" and "When the funnel tip passed over things, they would whoosh straight up like they were on an invisible elevator."
All things considered, a tornado is basically a natural vacuum cleaner. Light items probably go straight up like rockets and cars and combines probably bounce around inside the funnel stratified by weight until their equilibrium is disturbed (a collision with more debris enter the base) and the item falls out.
I've seen footage taken by a news chopper looking straight down into the funnels of several small tornados. Very dark and lots of lightning in the larger funnels. I had always assumed that the funnels didn't have a top, even though that kind of makes no sense, only because very few people had ever seen a tornado from above.
When you see tornado tracks from the air, the curleycue marks left on the ground where the funnel tip scours the earth look like God was doodling on scrap paper. I'm not sure of the total "lift capacity" of an F5 twister, but I know that an F2 class storm lifted a car with two people in it over 9 stories and then dropped it, killed the passengers inside. There will probably be some good metrics on tornado lift since more and more "test devices" are getting sucked up and carried along, revealing more about the insides of tornadoes than we ever knew before:
http://blogs.discovery.com/storm_chasers/2010/05/dominator-fully-loaded-the-ultimate-tornado-research-machine.html
I did manage to find the video of a look inside the funnel:
http://www.huffingtonpost.com/2009/06/08/rare-look-inside-a-tornad_n_212538.html
I also found a lot more sites with good daylight photos.
http://cache.boston.com/universal/site_graphics/blogs/bigpicture/iowa_06_17/iowa1.jpg
The above photo shows how close people are getting to the funnel with cameras in very good light. I don't think this funnel had begun sucking up debris yet.
Here's another broad daylight encounter:
http://images.pictureshunt.com/pics/t/tornado-12431.jpg
and another
http://s.ngeo.com/wpf/media-live/photos/000/001/cache/dakota-prairie-tornado_127_600x450.jpg
The problem with tornado photos is that to see detail in the debris cloud you have to frame the shot so that you can't see the funnel anymore. Most people keep the focus on the funnel and not on the debris. Also, if you are close enough to the debris cloud to get good pictures, you're close enough to get hammered to death by a whirling cow, truck or water tank. Who hasn't seen a clip that shows white-knuckled twister chasers screaming "IT'S FOLLOWING US!!!!?" when a twister they have been chasing turns the tables and starts chasing THEM.
-- Bobby G.
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Robert Green wrote:

...
Not really. There is reduced pressure, true, but afaik there still are not really definitive measurements of the actual minimum pressures to be expected in the core vortex. There are eyewitness accounts from folks said they watched their aneroid barometers during an event that claim as much as 5" Hg drop, but all the vortex models and what data have been collected are significantly less than that (more on the order of 100 mbar for F5-scale vortices).
The bulk of the damage and the tendency to move things is the bulk wind velocity air pressure force. The legend that the pressure drop "explodes" houses is just that; in reality, roofs tend to come off and the damage looks like it's from the inside out because of the lift force from the Bernoulli principle--lower pressure generated by higher velocity owing to shape differential. It's the same thing as airplane wing lift force.
Yes, there are lots of photos in daylight; I've seen a number myself. Thing is, there aren't many that actually show the movie scenario of that kind of stuff rotating around in the middle simply because even in daylight by the time you have that much stuff in the air there's so much dirt and small debris the visibility is occluded. Eventually, one of the watch/chaser instrumented packages or vehicles will indeed get some footage but I'm not holding my breath on seeing the bus and the cow circling one another as in the movie.
Yes, there are seemingly incredible events; a sheriff's officer in his car was killed while trying to serve as early warning by a second EF-5 spawned N of Greensburg the same evening. It ended up some mile or so off the road from where they think he was parked. An automobile is light enough that indeed it can become airborne but again, it's almost all wind forces, not "sucked up" by the pressure differential. Heavier items also get carried along and thrown around because they have larger surface area.
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clipped

Heck, just leave the cell phone and digital camera on the porch next time there is a T warning :o)

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Definetly NOT!

They had to freeze the frame and draw little circles around the items in the debris cloud, but once they did, you could easily pick out the large vehicles. The amount of "real world" tornado footage has increased dramatically because of cell phone cams, security cams and consumer cams with video clip ability. I know the scene of a family scrambling to get up under an overpass was real - you could see the grass flattening and hear people screaming for their lives as the twister rode right up on top of them.

When you see a pickup truck whirling around 100's of feet off the ground it sticks in your mind. You can easily see large chunks of debris silhouetted against a clear sky in some of the pictures you'll find here:
http://www.google.com/images?q=airborne+tornado+debris
especially:
http://www.tapestryinstitute.org/tornado/images/debris.jpg

That's true of many tornadoes, but it's clear that some of them present very good displays of what's whirling around in the debris cloud.
That site says: "F-3 or F-4 tornado in Pampa, Texas on June 8, 1995. Scale is deceptive; larger pieces of debris in this photograph are vehicles that were picked up from an oil company parking lot and large sections of sheet metal roofing, according to photographer Alan Moller, a National Weather Service employee and storm chaser. Video taken of that same funnel by a sheriff on the scene clearly shows pickup trucks and vans airborne at an altitude of 80 to 90 feet off the ground: the height of an 8-story building."

Yeah, but they obviously aren't all like that.

Watch more Weather Channel! (-:

I've seen plenty of footage like the Pampa shot where the debris cloud is perfectly illuminated. The problem is that the photos are usually taken from so far away that it's hard to see what's rolling around the funnel until you magnify them. They don't look like the close-up and obviously FX shots in the movies. I am sure you'll eventually see the footage I am talking about and be able to pick out the trucks, car, vans and other huge items that tornadoes routinely pick up and spin.
Here's one of the most magnificent tornado photos I have ever seen:
http://listverse.files.wordpress.com/2009/11/tornado.jpg
-- Bobby G.
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That is awesome!
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wrote:

That is awesome!
Can you imagine looking out your window at a night thunderstorm and seeing THAT thing lit up by a large lightning bolt? When you're that far away you could be easily completely unaware that a funnel that size was nearby. I think I might soil my union suit - it's the ultimate boogeyman.
-- Bobby G.
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On Fri, 4 Jun 2010 03:34:54 -0400, "Robert Green"

Map path for Donna: (NOAA) -- include other states
http://www.nhc.noaa.gov/HAW2/english/history/donna_1960_map.gif

David skirted Miami Dade County by 50/75 (?) miles. The storm never made landfall in South Florida. I slept in a cell, collected overtime, holiday pay and then went home after 12-16 hours.
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PRAY PRAY PRAY PRAY PRAY PRAY PRAY and PRAY
On Fri, 4 Jun 2010 03:34:54 -0400, "Robert Green"

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