is the only frozen precipitation that forms in warm
weather. It is produced by powerful thunderstorms that
result when a cold air mass clashes with a warm air
mass. The precipitation in thunderstorm clouds begins
as ice crystals. These crystals attract water droplets
to form raindrops and melt as they fall to the earth.
However, in some storms, the upward wind currents are
so strong that ice crystals are blown back up several
thousand feet into colder air, where another layer of
ice forms around them. The crystals bounce up and down,
as if they are on a "trampoline of air", growing larger
and larger. When the crystals become so heavy that the
upward currents can no longer support them, they fall
to the ground as ice pellets that we call hail. Wind
patterns usually form hailstones into balls; but they
can also appear in other shapes, such as cones, discs,
stars, pyramids, or just weird, pointy blobs.
The more violent the thunderstorm, the stronger
the updrafts and the larger the hailstones are. Although
most hailstones measure less than an inch in diameter,
golfball-size hail is not unusual in "Hail Alley," the
area made up of northern Colorado, southeastern Wyoming,
and western Nebraska. Occasionally, halistones are the
size of baseballs, softballs, or even grapefruit. Obviously,
hailstones of almost any size can be dangerous and destructive
shattering windows, smashing automobiles, and
injuring, or even killing, people and animals.
Perhaps the most unusual hailstone ever
reported was the one known as "the human hailstone."
This event occurred in Germany in 1930 and gives us
a terrifying look at the enormous forces at work in
a thunderstorm. As sixteen glider pilots flew in a contest
to see who could reach the highest altitude, strong
winds carried them into storm clouds that were forming
over the mountains. Sensing the danger of the powerful
updraft, fourteen of the pilots quickly steered their
planes out of the current and out of trouble. But two
pilots were pulled into the storm system and trapped
in currents of swirling air that lifted them to an altitude
of 40,000 feet. Their gliders were blasted apart by
the winds, and both pilots tried to parachute down to
safety. One of them made it. The other was carried up
into a cloud, where heavy layers of ice formed on him.
He then fell 7 miles to his death A HUMAN HAILSTONE!