[Scan-DC] [OT]I wouldn't have believed it unless I'd seen it

[b_thom at juno.com]

On Wed, 8 Jun 2005 05:18:05 -0700 (PDT) Shawnerz <shawnerz at yahoo.com>
writes:
> Then came the sand storm.

I immediately thought of that.

> The question I cannot answer is, how did this happen?

No answer from me, but the eruption of Mt. St. Helen's had a similar
electrical display, did it not? I must Google one of those sites.

Google for "volcano lightning" or "volcanic lightning."

http://volcanology.geol.ucsb.edu/lightnin.htm

Volcanic Lightning
Electrical discharges can form awesome shows during eruptions. Some of
the most spectacular examples have been at Sakurajima volcano, Japan. The
effects can be spectacular when there is abundant fine particles within a
strongly expanding eruption cloud. It is thought that friction between
particles and gases cause potential differences that create the lightning
displays. Lightning bolts travel in any direction, and occur in different
shapes -- broad bolts, St. Elmo's fire (ball lightning), as separate
small sparks, branching displays such as at Sakurajima and others.
Lightning can strike the ground and be a hazard to life, but it most
commonly is only a hazard to communications and to human anxieties, for
the lightning occurs between clouds and from the eruption column to the
crater.

Further Reading
Blong, R.J., 1984. Volcanic Hazards. Academic Press Australia. 424 pp.
(see text on pages 62-64 with more references).
Gilbert, J.S., and Lane, S. J., 1994, Electrical phenomena in volcanic
plumes, in Casadevall, T.J., ed., Volcanic ash and aviation safety:
Proceedings of the first International Symposium on Volcanic Ash and
Aviation Safety: U.S. Geological Survey Professional paper 2047, p.
31-38.