> Artist fails to generate 2km column of steam.
> http://m.bbc.co.uk/news/entertainment-arts-22152127

I'd say he was lucky :-).

I recently saw what started as a "dust devil" turn into a respectable
mini-twister perhaps 100 metres + tall and only perhaps a metre or so
across. At ground level it was initially a several metres across
dancing whirl of leaves and dust and balloons (at a fair). It rapidly
formed a tall thin twisting white-opaque column. Dust etc could not be
seen at height but it sucked in loose balloons and released them high
in the air. The appearance was very tornado like. (I had a (probably
futile) action plan worked out ... :-) ).   I don't know where these
things end and urban tornados (such as we get here very very
occasionally) begin.

'My' one was on a hot summers day on a grass surface in an area
shielded from wind with many people present. Duration was perhaps a
minute or two each (several formed sequentially).

How you stop a "steam" spout becoming detached and voracious I know not.

Having seen how 'my' one formed and the general conditions I suspect
it would be possible to form them artificially under good conditions.


          Russell
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