Upside down tornadoes?

[Elaine Spencer]

Here's a quick question for everyone. My husband just discovered video of what was purported to be an "upside down tornado" on YouTube:

http://www.youtube.com/watch?v=UqJTYsDPEaQ

I didn't think it was possible for a tornado to actually form UPWARD from a cloud. I suspect that what actually happened here was that the rotation originated in the clouds ABOVE the wall cloud. When the vortex got going it sucked up part of the wall cloud -- the same way it would suck up a cloud of dust or debris if it reached the ground. Is this correct, or is there another explanation? Has anyone on this forum ever seen an "upside down" tornado or funnel cloud like this?

 

[Dan Robinson]

That looks more to me like a laminar arcus cloud getting pulled into an updraft. I can't tell for sure, but it doesn't appear to be rotating. I've seen similar 'peaks' on arcus clouds before, but none that got stretched so far upward like that. Whatever it is is pretty unusual.

 

[Skip Talbot]

By definition, the base of that would have be in contact with the ground for it to be a tornado, (in addition to there being some sort of tornadic rotation). An inverted funnel cloud seems entirely possible though given that vortex arches and loops and tubes form in a myriad of angles and configurations in storms. Bow tie funnels for example, where funnels kiss each other in a ring, could be mirrored about the horizontal and appear to be upside down, but usually there is cloud above them, which would obscure that view.

In this case, the parent cloud looks like arcus, a shelf or roll cloud and not a wall cloud, seeing that it's detached from the parent updraft tower. i was going to say that I've seen clouds that have looked like this before, until midway through the video the feature became extremely pronounced, and that I have never seen. Often times, these clouds are shaped by being forced upwards by some sort of mechanical lifting process. This forcing produces a very smooth, laminar cloud. I'm just guessing here, but an updraft above that arcus may be forcing that cloud upwards. If there is rotation in that feature, and it's hard to make out in that video, it's probably non-tornadic. The day this video reminds me of is May 12, 2010 when we saw some laminar, forced clouds in the wake of a severe warned thunderstorm:

Watch video >

At about 1:19 you can see a detached cloud with a nice pointy top. There was probably some sort of updraft above it, forcing that feature upwards into a point. These clouds are sitting above a stable cold pool, however, so the tornado threat here is near zero. I imagine there were similar conditions in the video in discussion as an arcus usually rides atop a stable cold pool.

 

[mikedeason]

Pretty neat looking. The first thing that popped in my mind was Kelvin-Helmholtz instability.

 

[Bob Hartig]

Now that is pretty neat! The roll cloud appears pretty standard-issue, and at least this part of the storm doesn't look at all tornadic. I agree with the idea that part of the roll cloud has gotten caught up into some kind of updraft, maybe some localized effect of warm inflow overriding the advancing gust front. But it's possible that some kind of vorticity is also influencing the updraft, causing it to rotate--the hose-like appearance suggests as much to me, though I can't tell one way or the other from the video.

I don't know what you'd call that other than mighty darn cool and also quite pretty.

 

[Jeff Duda]

I agree that it's also probably the result of vorticity within the arcus cloud that somehow got tilted into the vertical. Perhaps there was just enough buoyancy within the roll cloud and a dry/cool layer above it to support some kind of microscale gravitational instability. Or perhaps there was a dynamic vertical perturbation pressure gradient force strong enough to force the updraft. I don't know the day or specific location of the video, but there looks to be some decent convection immediately behind the feature, so this hypothesis isn't all that far-fetched.

 

[Joshua Nall]

I'm sure most of you have seen Mike's photos of his "Fog storm". The seventh photo down at this link looks quite a bit like the cloud in question in this video, like a mountain peak, although not as extreme. Mike's photo here could probably be described as an arcus cloud with a lot of fog around it, under it. I've seen some pretty wild roll clouds before, not like this, but they can become molded into weird shapes by the near storm environment.

http://www.extremeinstability.com/08-6-18fogstorm.htm

 

[Bob Hartig]

After looking at the video clip for a second time, I'm inclined to believe that the feature is indeed some kind of vortex. The tip of the "wave" links up with the cloud base directly above it from about 2:00 on, and if you look closely, you can discern what appears to be an extension of the tube continuing to arc off to the left. I note that the higher cloud base is somewhat localized and doesn't extend over the next "wave" to the left. Seeing actual rotation would be the clincher, but the video isn't clear enough to reveal either rotation or the lack thereof; however, the tubular appearance of the mature formation is consistent with a vortex. It's more than just a strikingly tall, peaked formation--the peak morphs into an actual tube, from what I can see. I like the idea of vorticity overriding the roll cloud and getting stretched into the vertical by an updraft, drawing cloud material into it.

Whether I'm right or wrong, that is the darndest thing. Thanks for sharing it, Elaine--it is truly a unique video clip.

 

[Joshua Nall]

Yesterday I was watching it on the lowest quality setting and my computer still would not load it all the way. I can see now that it does appear to be a tube rather than just a peak of cloud material being pushed or drawn upward. Would have been great if they had stopped and zoomed on the upper section.