Anatomy of a Thundercloud
Puffy fluffy cotton clouds are mainly water.
Gray gleaming gloomy thunder clouds are mainly ice.
Precipitation, each drop or flake of it,
first tumbles from its cloud as ice, in the nature of sleet.
Thunderclouds are composed of sleet,
suspended dynamically on a column of air,
which oftimes fails, locally collapses a layer at a time,
leaving the particles of sleet suddenly unsupported in the sky.
Insensate, an inanimate object,
the sleet does not get a chill up the spine,
a clenching in the gut,
a pang in the instep as it begins its fall.
It just falls.
Buffeting its way down through warmer air,
the crystal of ice melts to liquid, and pops to the surface as a raindrop.
In the deadly and mysterious regions of the frozen North,
the sliver of sleet fails to melt,
but accrues other ice in a disc radially,
microscopic whiskers and sheets in symmetry,
to form the dreaded snowflake, instantly toxic to all higher forms of life.
Some inferior species, such as polar bears and Yankees,
have been forced to develop a tolerance to its lethal effects,
after generations of being shoved from habitable regions by their betters.
These creatures seem immune to exposure to any amount of solid water.
If the seed crystal is whipped by updrafts, it may grow to a hailstone,
after dropping a mile, and being spewed up again
by ferocious vertical winds inside a thundercloud.
After several cycles of this giddy ride,
the hailstone is heavy enough to drop out of the cloud,
and tumble to your windshield.
Puffy fluffy clouds are water, grim gray clouds are ice.
The electric power of the sky hovers menacingly in ice clouds.
The dynamo of thunderstorms is triboelectric,
which is to say static charges are exchanged by brushing or rubbing,
in this case of ice.
Storm clouds are made of ice and air, nothing else.
The same tiny pellets of sleet,
the same ones which may be destined to melt into raindrops,
stretch into snowflakes,
or glue into hailstones,
are yet at rest,
balancing their weight on the steadily rising river of air inside the thundercloud.
The wind which holds them up is full of ice dust, blowing toward the statosphere.
Lacking energy to erode away the sleet pellets,
the dust jostles them like minute pickpockets, invisibly stealing their electrons.
This stolen charge is wafted straight up,
a mile or two miles higher, but still inside the thundercloud.
An enormous force of nature wants those electrons back.
Pulled down by inconceivable voltage, a spark of electrons may find a channel
of slight weakness in the air
and return to the sleet pellets from which they were stripped
making the descent of a mile or two in a spectacular hurry.
Electrons in a hurry don't wait around.
They scorch the air on their way through,
blasting its ions aside for ashes,
punching for themselves a tunnel through the very air itself.
Electrons in a hurry like to travel in a vacuum,
and if they don't find one handy they kind of make their own.
The flash of light you see isn't the electrons traveling.
They've already been by that way.
You see a fossil of their track,
as the shredded ions snap back to atoms,
the atoms reassemble to molecules,
making air again of a sort.
This air of sorts crashes back into the hole
punched through it by electrons in a hurry.
The crash of air slapping on thin air can be heard for miles.
It can put a chill in your spine,
clench your gut,
send pangs up from your insteps.
One lightning stroke in ten gets kind of lost
and wanders away from its cloud to hit the earth.
It's hard to steer electrons which are in a hurry.
A lightning stroke is a dozen lightning strokes.
A dozen pockets of excess electrons in the upper cloud
empty themselves through the same crooked channel
blasted through the sky, since it's handy.
To an electron in a hurry, it looks as good as a copper wire.
The purpose of thunder is to give you a hint of the power hovering in that cloud.
A thundercloud is made up of air and ice.
There's nothing else there.
 |
 |
 |
rev 980309
