Tornadoes with Tentacle Like External Vortices!!

[Bill Tabor]

Ok, we've all seen the dramatic Tuscaloosa tornado with it's squid like external 'tentacle' vortices. That tornado IMO looks incredible as tornadoes goes and likely ranks amongst the very top, but what are those freaking War of the Worlds like tentacles? I don't remember seeing tornadoes sporting those in the past. The first time I saw them was last year on my Goodnight Tornado. I loved them then, but the Tuscaloosa torn has them all over and they seem to be fairly long lived and generated regularly? What are these things? Can anybody explain them? How many of you have seen or chased tornadoes with them? Show your pics! Seriously this seems like some cool stuff. Perhaps they are a sign of a very violent tornado or perhaps a type of multi-vortex with one main parent circulation? However, unlike satellite tornadoes these typically are not on the ground. Makes me now wonder again about the Ft Leonardwood tornado pic and it's odd vortex crossing it. If anyone knows the science of these things...let's here it please. Here's a pic of my Goodnight torn (it had many faces and looks during the 20 minutes it was down).

 

[Dan Robinson]

I'm wondering if this is somewhat of a "smoke ring" effect, with rapid upward motion causing 'rolls' to form around the perimiter. A smoke ring forms with a rapid 'puff' of vertical air through stagnant or slow-moving air, with this tornado it's as if the 'puff' was a steady stream of high-velocity air interacting with slower-moving air along a sharp boundary.

 

[rob.cannon]

I did some Googling and I found that many of large violent wedges in the past have been reported to display these types of features. I saw a few of them on June 17th in Southern Minnesota, but nothing as prevalent as on the Tuscaloosa tor. Upon further searching the only explanation is they are just suction vortices. Thats all I have.

 

[DRMabe]

It was pretty wild watching them wrap around that thing. Took some still captures from my vid of them.

 

[Mike Krzywonski]

If I had to guess, I would say that it's extreme stretching of horizontal vorticity. Typically, when we think of mesocyclones, we think of the tilting of environmental horizontal vorticity (caused by the vertical shear of the horizontal wind) and subsequent stretching of this newly-converted vertical vorticity (the dw/dZ or dB/dZ term). In this case, I can only think that the low-level / near-surface horizontal vorticity (or vertical wind shear near the surface) is so extremely strong that it ends up getting stretched INWARD towards the tornado as a result of extreme horizontal (radial or tangential) inflow. In other words, imagine taking a roll of dough, grabbing one end of the roll, and pulling it outward. In this case, there may be natural "rolls" (perhaps something like a vortex sheet aligned horizontally, with occasional "roll-ups"), and the horizontal acceleration of the wind associated with the tornado is so intense that the vortex tube, of sorts, gets stretched enough to drop the pressure low enough to produce condensation (the tubes that you can see). Actually, like vertical stretching, we are really talking about the gradient in horizontal wind resulting in horizontal stretching. Of course, vertical motion associated with the tornado can then tilt this already-condensed tube upward, resulting in these spiral-tube formations. Again, just my hypothesis.

This was brought up in the DISC. thread.

 

[rob.cannon]

It was pretty wild watching them wrap around that thing. Took some still captures from my vid of them.

watching it live form the tower cam was incredible! I was thinking "an already violent tor is about to spawn a good sized satellite... this day is about to go from bad to really bad!"

 

[Bill Tabor]

Unable to insert a picture last night, or this morning of my Goodnight tornado with external vortices due to ST performance issues and lockups. Here is the link to it as an example in a addition to Tuscaloosa:

http://www.tornadoxtreme.com/20100422_163313.jpg

 

[Bill Tabor]

Anybody have any other examples of this to post. I'm almost wondering if this is some type of new phenomenon. I know that doesn't make sense in regards to atmospheric physics but how come only recently torns have it, or am I mistaken. What about those wedges mentioned. Provide a link...what year and what tornado? Are these extremely rare?

 

[Scott Weberpal]

Anybody have any other examples of this to post. I'm almost wondering if this is some type of new phenomenon. I know that doesn't make sense in regards to atmospheric physics but how come only recently torns have it, or am I mistaken. What about those wedges mentioned. Provide a link...what year and what tornado? Are these extremely rare?

We're seeing them more and more now because there is more and more up-close and high quality video being taken of strong tornadoes.

Going back only 10 years...would there have been much, if any video of the tornado in Tuscaloosa compared to what was taken a few days ago?

Mulvane '04

http://www.mesoscale.ws/pic2004/040612-13.jpg - look at the upper half of the tornado.
http://www.mesoscale.ws/pic2004/040612-14.jpg - zoomed in with "tentacles" everywhere.

Red Rock '91 had a substantial horizontal vortex, and I believe that if Prentice/Rhoden would have been closer, you would have seen "tentacle" whipping everywhere around the tornado.

There is nothing to indicate that only recent tornadoes have these "tentacle", except much more fantastic video. Some tornadoes have them and some dont', and with better and more video, we'll see more and more of the tornadoes that do.

 

[Jeff Duda]

Anybody have any other examples of this to post. I'm almost wondering if this is some type of new phenomenon. I know that doesn't make sense in regards to atmospheric physics but how come only recently torns have it, or am I mistaken. What about those wedges mentioned. Provide a link...what year and what tornado? Are these extremely rare?

This is nothing new. I can remember seeing such auxiliary vortices on tornadoes from videos I watched when I was a kid of tornadoes in the 70s, 80s, and 90s. Haven't you seen Bobby Prentice's video of the Red Rock F4/5 tornado crossing I-35 on 26 April 1991? http://www.youtube.com/watch?v=5zUJJH_MSZI

 

[Bill Tabor]

Scott / Jeff, yep, I see the Mulvane torn does appear to have some smaller ones up top half although mostly minor. Red Rock I had never seen. Pretty cool and it does have one decent horizontal vortex which dissipates. My Goodnight torn had these much wider around the tube and larger vortices compared to Mulvane (not just in that picture). Tuscaloosa though appears to be an extreme example with these things being consistently hanging off multiple sides at the same time. I was thinking about it and that tornado kind of reminds me of the old War of the Worlds movie where the guy is holed up in the farmhouse and one of those aliens comes running through the room with his tentacles swinging / dangling.

Still seems this is a rare phenomenon - unless we have more and better examples. I wonder if it is any indication of strength, etc.

 

[Chad Ringley]

The Mulvane tornado developed those vortices in conjunction with a substantial kink in the main circulation up top. I remember thinking when seeing it that it had something to do with that kink. Wildest thing I've ever seen.

 

[Kevin Walters]

I talked to a farmer back in the mid 80's who witnessed the Charles City, Iowa tornado in 1968. His farm was in Southern Floyd county about 20 miles SW of Charles City. The tornado missed his farm by one mile to the North. He described it as having "spider legs" moving out away from the tornado itself. Sounds similar to what happened with some of the tornadoes this week.

 

[Joshua Nall]

Sorry if this has been posted already but I've not seen it linked yet, could have missed it. It has over 3 million views so it's a popular one.

http://www.youtube.com/watch?v=5ohIVzIZLuQ&feature=player_embedded

The video is shaky, sounds like a woman, who is very shakin' herself being so close to this violent tornado. But the middle part of the video ranks up there with the most violent video I've ever seen.

As for all the external vortices. I'll put it into terms that I understand. Seems to me the air accelerating in so incredibly fast at ground level, and then spiraling up into the tornado causes the horizontal rolls... just like at the back side edge of a paddle through water. Seems logical to me the most violent tornadoes would have these... cause the rolls get tight enough, intense enough to become visible with condensation. What I'm describing is probably the same thing as the smoke ring effect Dan mentioned. I think the Mulvane vortices are something a little different in that they are not associated with the mostly horizontal wind speed along the ground. Just me thinking out loud.

 

[Bill Tabor]

I talked to a farmer back in the mid 80's who witnessed the Charles City, Iowa tornado in 1968. His farm was in Southern Floyd county about 20 miles SW of Charles City. The tornado missed his farm by one mile to the North. He described it as having "spider legs" moving out away from the tornado itself. Sounds similar to what happened with some of the tornadoes this week.

That may be that 'dead man walking' phenomenon. Similar but multi-vortex on the ground rather than tentacles dangling in the air. Dead man walking is legendary bad ass too - per Indian folklore.