Largest dusty I've seen

[DieselFan]

Following on some comments about today's weather...on returning from a lovely flight I saw the largest dust devil ever! It was around 15m+ wide and over 400ft very visible, fading off at around 500ft.

It looked like a twister from, well, the movie Twister. The twisting was severe and warped and took the shape of a tornado, from the pics I've seen! The "twister" was visible for almost 2 minutes and covered around 600m +- 20km/h. It was just south of Bapsfontein +-3km.

It was most amazing and I tried my best to look, but no cows were flying around.

This was around 14h00, Also a first was having to abort 2 landings due to normal devils on the runway. Wish I had my camera.

Atleast it's warming up and gloves can get thinner and soon we'll fly after 18h00!

[DieselFan]

It looked kinda like this one - thanks wikipedia.

http://en.wikipedia.org/wiki/Dust_devils


"They are comparable to tornadoes in that both are an unusual weather phenomenon of swirling air vortices. Tornadoes form as an updraft attached to a wall cloud at the back of a thunderstorm. Dust devils form as an updraft under sunny conditions during clear to fair weather, rarely coming close to the intensity of a tornado."

All 3 conditions were met
- Flat barren terrain (Farms)
- Clear skies
- Light or no wind and cool atmospheric temperature

[Dre'man]

Didn't you in one of your previous posts want to learn to thermal?

[Nkwazi]

Could it invert you??

[Nkwazi]

Now what now??

[Cali]

Hi Bennie

In the Part of Western Australia where I live the are very common. I have seen eight of them going at one time. They are big but not dangerous (if you are on the ground) I wouldn't want to fly into one though.

They call them Whirly Whirly's here.

[Nkwazi]

I thought you meant it happened in the air and I meant to say "nou wat nou", what did you do??!! Still, it flipped you over on the deck, eish.

[DieselFan]

Dre'man, I don't think I'll learn much about thermalling in there

If these large ones lift around 15 tons of sand, a 300kg trike is nothing.

How does the magnetic charge generated by these things affect us? Does it pull on a trike / plane and stuff up it's electrical systems?

"Dust devils, even small ones (on Earth) can produce radio noise and electrical fields greater than 10,000 volts per meter"

Personally it looked fascinating and would love to see another - from a safe distance. These large ones however are very intimidating esp when they're higher than a trikes normal flight level.

Are dust devils strong enough to lift objects like humans - ie no large surface area'd wing.

[John Boucher]

Maybe Boet can comment on the Dust Devils....

I travelled down to Cape Town via Brandvlei - Calvinia and there is an area called the Verneukpan. Some might recall about the Jetdragster wiping out there not so long ago.

This specific day I counted no less than 18 Devils popping around at one time. Must say that it was in summer and obviously with the scorched earth there, anything is possible.

Check out the plains on Google Earth.....

[Arnulf]

Just a sobering thought on this topic: We call them "dustdevils" because of the dust that gets sucked up, and makes them easy to see. However if there is no dust around, ie too much vegetation or wet ground etc. you can have the same phenomena without the dust, ie you are blissfully unaware of their presence.

[John Boucher]

That is called serious turbulence!

Where is the plastic bag....... ?

[DieselFan]

Has anyone else seen one of these large ones? I'm dying to fly again and take a pic!

Arnulf I think I was once hit by the non visible type, not a normal thermal. I was flying 90 degrees and within a second flying 220.

Provided you have height is it safish to fly through, I'm not meaning intentionally but by accident, what to do?