Hailstorms occur when strong thunderstorm updrafts carry water droplets above the freezing level, where they freeze into hailstones. Hailstones grow larger as additional water freezes onto them until they become too heavy to be supported by the updraft and fall to the ground. Hail has the potential to severely damage crops, plants, buildings, vehicles, and can even cause injury or death. Mitigation efforts include educating people on sheltering safely during hailstorms, issuing warnings, and designing buildings to withstand hail impacts in prone regions.
2. HAILSTROMS
• Hail is a form of solid precipitation. It is
distinct from ice pellets, though the two are
often confused. It consists of irregular lumps
of ice, each of which is called a hailstone.
Ice pellets fall generally in cold weather
while hail growth is greatly inhibited during
cold surface temperatures.
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4. Contd….
• Unlike other forms of water ice such as
graupel (soft hail), which is made of rime,
and ice pellets, which are smaller, hailstones
usually measure between 5 millimetres
(0.2 in) and 15 centimetres (6 in) in
diameter. The METAR reporting code for
hail 5 mm (0.20 in) or greater is GR, while
smaller hailstones and graupel are coded
GS.
5. • Hail is possible within most thunderstorms
as it is produced by cumulonimbus cloud
(Vertical cloud), and within 3.7 kms of the
parent storm. Hail formation requires
environments of strong, upward motion of
air with the parent thunderstorm and
lowered heights of the freezing level. In the
mid-latitudes, hail forms near the interiors
of continents, while in the tropics, it tends
to be confined to high elevations.
6. • There are methods available to detect hail-
producing thunderstorms using weather
satellites and weather radar imagery.
Hailstones generally fall at higher speeds as
they grow in size, though complicating
factors such as melting, friction with air,
wind, and interaction with rain and other
hailstones can slow their descent through
Earth's atmosphere.
7. • Any thunderstorm which produces hail that
reaches the ground is known as a hailstorm. Unlike
ice pellets, hailstones are layered and can be
irregular and clumped together. Hail is composed
of transparent ice or alternating layers of
transparent and translucent ice at least 1 millimetre
thick, which are deposited upon the hailstone as it
travels through the cloud, suspended by air with
strong upward motion until its weight overcomes
the updraft and falls to the ground.
8.
9. • Hail forms in strong thunderstorm clouds,
particularly those with intense updrafts, high
liquid water content, great vertical extent,
large water droplets, and where a good
portion of the cloud layer is below freezing
0 °C (32 °F). These types of strong updrafts
can also indicate the presence of a tornado.
The growth rate is maximized where air is
near a temperature of −13 °C (8.6 °F).
HAIL FORMATION
10. Contd…
• Hail forms when thunderstorm updrafts are
strong enough to carry water droplets well
above the freezing level. This freezing
process forms a hailstone, which can grow
as additional water freezes onto it.
Eventually, the hailstone becomes too heavy
for the updrafts to support it and it falls to
the ground.
11. IMPACTS OF HAILSTORM
• Hail is one of the most feared weather
phenomenon's because it has the potential to
destroy plants, trees, crops, animals and
human life upon impact if strong enough.
This can have an adverse effect on the
ecosystem if the damage is severe.
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14. IMPACTS OF HAILSTORM
• Most humans are able to seek shelter when a
hail storm hits. However, if you’re unable to
run for cover, sizable hail can injure or even
kill you!
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16. IMPACTS OF HAILSTORM
• Birds, livestock and other animals are unable to
seek proper shelter during this kind of weather, and
they are typically among the devastation that is
brought on by a huge hail storm.
20. HAIL SUPPRESSION
• In order to prevent hail damages, it is
necessary to transform the dangerous
convective clouds so as not to allow the
formation of large hailstones. Usually, the
number of ice crystals in the cloud is small
and, upon the existence of appropriate
conditions, they grow rapidly to hailstones
with large sizes.
21. BENEFICIAL COMPETITION
• Seeding increases significantly the ice
embryos concentration so that the artificial
and natural ice particles compete with each
other for available liquid water. The super
cooled water redistributes between all ice
embryos and thus resulting hailstones are
small. Falling to the ground, they melt to
rain.
22. EARLY RAINOUT
• Seeding accelerates precipitation
development, resulting in the “rainout” of
still small hydrometeors from convective
turrets that have not yet developed updrafts
strong enough to support the growth of hail.
Thus, the cloud supercooled water content is
reduced.
23. TRAJECTORY LOWERING
• Seeding accelerates hail embryos growth at
lower level in the cloud, where liquid water
content is smaller and updrafts are weaker.
Then the hail falls out of the cloud both in
smaller sizes and earlier than if that would
have taken place naturally.
24. Human Adjustments – Mitigation to
reduce the risk of Hailstorms
• In India, Hailstorms are common in northern
regions especially Uttarakhand, Uttar Pradesh ,
Himachal Pradesh and other states across
Himalayas.
• Hailstorm can cause injury to people and animals.
It will cause a heavy damage to the buildings,
vehicles etc. People who work and live outdoors,
people who are not aware of the storm are usually
vulnerable to hailstorm.
25. MITIGATION PROBLEMS
• Hailstorms are expected only during certain
seasons like February, march, September and
October. So we must need to arrange the
awareness programmes to people about how to get
shelter from Hailstorm when they are outdoors.
• Warnings need to be issued via televisions, social
media if it is forecasted by the weather department
• It is necessary to have people , buildings and other
things like vehicles protected from the damage
caused by hailstorm.
26. SHORT-TERM GOALS
• Establish centres to provide temporary
accommodation for houseless people.
• Shelters must be provided for emergency vehicles
like ambulance, fire service vehicles etc
• People must be alerted about the forecasts through
media like radio and television.
• Alerts can be given through SMS for outdoor
workers who may not have access to the
televisions or radio.
27. LONG TERM GOALS
• People must be educated about the disaster.
People must gain knowledge through which
they can protect themselves from the hailstorm.
• The buildings in hailstorm prone areas must be
designed in such a way that withstand
hailstorm. Proper parking areas must be
provided, roofs must be strong enough to
withstand the force of hailstorm.
