Jack said . . .

>>>>> It is quite common for a large wildfire to spawn
convective cumulus cells, dependent mainly on the instability and
moisture content of the overlying airmass, i.e., the more unstable and
moist the airmass above the fire, the more efficient the wildfire will
be in spawning convection. <<<<<

On the other hand, in the summer desert southwest, the air is typically
so unstable that I contend a horny toad scurrying out from under a rock
can create a thunderstorm. Just about any upward displacement of air, if
not torn apart by horizontal breezes, will be self-sustaining and grow into
a cumulus, if not a cumulonimbus.

Many times, I have watched a small, almost invisible, speck of white
cloud grow into a massive, 60,000 foot high thunderstorm in an afternoon,
full of WWIII-like lightning, dumping an inch of rain and hail every 10
minutes as it travels east across the desert.

The amazing thing is how much water one of those things can squeeze out of
the arid desert air, as it sucks air from miles around into its huge
chimney. (Of course, hot air holds a ~lot~ of water.) And to stand
~beside~ a dry arroyo as a storm works on a mountain top far away, and
experience a 6 foot wall of water, traveling from 10 miles away, come
screaming down that sucker at about 40 miles an hour. The term "flash
flood" has no meaning after actually seeing one of them.

Desert air-mass thunderstorms are something everyone should experience
at least once. Not as nasty as the midwest storms, but ultimately more
visible against the blue sky, and more beautiful -- and humbling.

Jerry Blinn
Silverdale


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