Help. What the @%&! is this?

[MJ Poore]

A nameless member of the public emailed this into the South African Weather Service. Crickey! I first thought it was a mega dust devil. Then I looked at the instability on the day in question, which was very high. Maybe it is a tornado, but I can't see the parent storm here. Could it even be a monster landspout, or is it a tornado? Any thoughts anybody??

 

[Danny Neal]

its definately not smoke so we can rule that out, ive never seen a dust devil like that before not to say it cant happen but that looks to "violent" to be your run of the mill dust devil, looks like its under some Cu as per the background, kinda looks like a mostly sunny day with towering Cu, if i had a logical guess i think it would be a landspout, again if you knew if there was a storm around there then maybe maybe it could be a weak tornado, do you have anymore info or can you obtain it? that might be able to get to the bottom of it...but judging by this pic alone, i would tend to lean toward a landspout, are they common around there??

 

[Caleb Lawrence]

Do you have any idea what the soil is like near where this happened? If the soil, sand or dirt isn't of a dark variety, I'd be willing to bet it was smoke. However, there does look like some outward circulation near the very base of the vortex in question...it still looks like a massive amount of smoke to me, though. If the fire was large or hot enough, it's enough to cause a dust devil appearance due to the updraft of heat (well, that's a big duh). I believe Mike Umscheid took some pictures of a large field fire that resembled a tornado some months ago.

 

[scott r currens]

The vortex and the hillside in the background are in a large shadow. Looking at the cu on the right and left side of the vortex it appears that there is precipitation (hook echo?) between the vortex and the cu.

Given the instability, large shadow (from deep moist convection) and precip near the vortex I am 97% sure this is a tornado. The next question is, "What type of tornado is this, mesocyclone or non-mesocyclone?” If I had to guess I'd say it is most likely a mesocyclone tornado but I'm on 65% confident in that answer.

Scott Currens
www.violentplains.com

 

[MJ Poore]

I don't think it's a petrol fire or anything like that, smoke drifts. The individual who emailed described it as a tornado (not in English). He or she has not returned any contact or name. Even the area is vague, just south of a place called Heidelberg, outside Johannesburg. It's just bush out there.

The only other clue was some metadata on the photo, it was taken on 8 Jan 2005 at 4pm. Here's the local sounding...could easily be a nado with conditions.

 

[Dan Robinson]

Do they have more pictures? A sequence of images would shed some light on motion/dynamics.

 

[B Ozanne]

Can anyone explain why its so dark?

If you are going to rule out smoke, I'd like to hear the reasoning behind that. Smoke doesn't always "drift," especially when it is being sucked into a vortex it's parent fire created.

 

[Andrew Herron]

Well, the dirt could be dark. Even with the background hill in the shadow, the dirt is still darker than normal. Also, if you look at the top right, you can see a dark outline, showing me a vortex. In the upper half you can also faintly see a criss-cross of the "dirt", again showing a vortex.

 

[Dick McGowan]

How about a fire/smoke whirl? Mike Umscheid has some good photos from last year of some:

http://www.underthemeso.com/gallery2/stormchase/chase05/2005jun30/

 

[B Ozanne]

How about a fire/smoke whirl? Mike Umscheid has some good photos from last year of some:

http://www.underthemeso.com/gallery2/stormchase/chase05/2005jun30/

That's pretty much what a bunch of us have been getting at.

 

[Dick McGowan]

That's pretty much what a bunch of us have been getting at.

O rly? Because I only see one person stating it could be smoke, others calling it dirt, and one calling it a possible tornado.

Perhaps some outflow boundary was nearby.

 

[B Ozanne]

A bunch of us, meaning me. First thing I thought when I saw that photo was smoke. Looks way to dark to be dirt. Not that dirt isn't dark, but when it is dry and you are throwing it into the air it isn't that dark.

Now, it obviously isn't just a smoke plume rising into the air. It has rotation, just like a dust devil.

 

[Brian Emfinger]

I definately think its smoke with some rotation from the intense heat as has already been alluded to. Looking at some soil maps..there doesnt appear to be much black soil in South Africa. Mostly it appears to be arid with reddish soils.

http://www.fao.org/docrep/008/y5998e/y5998e03.jpg < soil wetness

http://www.fao.org/docrep/008/y5998e/y5998e04.jpg < soil type map

There do appear to be some areas further south from Heidelberg (if it was taken there) that do have black soils (vertisols) but the general area in question it doesnt seem possible.

It really looks like smoke to me.

 

[Danny Neal]

i have retracted my statement about not being smoke after lookin at mikes pictures, for the reason that i thought a "smokenado" couldnt be that "perfectly symmetrical" i have seen many many fires and a couple of vortices like this but they were all disorganized and tilted off in the direction of the wind, i wish i had pics to show you, but after looking at mikes and looking at this, it looks relatively similar, the only problem i have is like in mikes picture there is a large fire there, here there is possibly a grass or brush fire, so i have kind of a hard time believing the WHOLE fire is caught up into a vortex.......thoughts? denials? anything?

 

[Andrew Herron]

Would the fire heat give the instability an umph?