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Dedications for Scribe Weekly Radio
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Summer
hail
By Wijke Ruiter
"Devastating huge hailstones swept down from heaven above Holland?? I would never have It was an imposing one; coming upon us in all ranging colours from white-grey to deep-black; whirling and swirling in a low sky; as if the end of the world was there. No time to feel scared yet; only deeply astonished, nailed to the ground, just watching; this can't be real. Sudden heavy wind gusts raged along; rousing: a sense of danger flashed through the mind; we rushed into the house, just before white tennis-balls plopped on the green. "White tennis-balls"?? It was hailstones." Damaging hail Hail in summer; is this normal? Hail showers are quite common over Britain in westerly and northerly airstreams in winter or in early spring; but during the summer there can be hail as well, however not so often and, what's more, the hailstones can be much bigger than in wintertime.
These bigger hailstones are far more dangerous and can devastate
whole area's; damaging everything that's around. There are places on
earth
where large hailstones are quite common; mostly regions where
tornado's
are active, or in tropical and sub-tropical countries. Wine- and
orange growers in Italy, Spain and France have developed special
methods
to prevent the demolition of the vintage.
In our regions
storms with huge summer-hailstones are quite unusual, but
sometimes
it can go beyond any control. Chances
of
hailstones of about 1 inch (2,5 cm) are only a few percent; and
chances of
stones which are about 1,2 inch (3 cm) are three to five times
smaller;
but the damage this odd bigger hailstones bring grows very fast with
the
size. That's due to the bigger mass and the increasing
velocity. With such a speed, its easy to envisage that these large stones can dent cars; destroy greenhouses, roofs, plants, crops; really everything that's in its way down. People can get injured, and animals, especially birds, can easily be killed in a heavy hailstorm. Where does hail actually come from?
A
hailstone in profile Where do these stones fall? Almost
every
summer larger hailstones - of about 1 inch - will fall somewhere in
our
region but tend to occur mainly in the south of Britain, about four to
five times a year. The largest hailstone recorded
in
the British Isles weighed 142 grams (5 oz), was about 3 inches, and
occurred at Horsham, West Sussex on 5 September 1958. The USA, Canada, central Europe, the southern parts of the CIS, India and China all experience large hail. So too do land areas in the southern hemisphere. The world record (as quoted in the 1994 edition of The Guinness Book of Records) occurred in a hailstorm in the Gopalanj district of Bangladesh on 14 April 1986. The hailstones weighed up to 1 kg (2 lb 4 oz) and were reported to have killed 92 people.
wijke@scribeweekly.com
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Large
hailstones develop in huge thunderstorm-clouds. These clouds are
cumulonimbus clouds. In such a cloud are falling and rising
airstreams;
called down- and updrafts. The cloud base may be 2,000 feet
above
the ground with tops at 30,000 feet. Much of the cloud will be
composed of
super cooled water droplets. As the hailstone falls it will collect
tiny
water droplets which freeze and form a layer of ice. Perhaps the
hailstone
will then be caught in a vigorous updraft. As it is carried back
higher
into the cloud, it collects more minute water or ice particles to form
another layer of ice. Thus layers build up on the hailstone ice)
and
the cycle may be repeated until the stone is so big that the updraft
can't
lift it anymore; and it'll fall to earth. 
second
case the stone catches water droplets that form a layer of water
around
the stone; this layer freezes to the stone. In that stadium the stone
is
down at the bottom of the cloud.