QUESTION
Explain the mechanism and occurrence of cloudburst in the
context of the Indian subcontinent. Discuss two recent examples. (250 words, 15 marks)
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Introduction:
· A cloudburst
is a localised but intense rainfall over a small geographical area that can
cause widespread destruction, especially in hilly regions where this
phenomenon is most common. · According to the Indian Meteorological Department, if 10 cm of rainfall is received at a station in one hour, the rain event is termed a cloud burst. Predicting the cloud bursts is difficult due to their very small scale in space and time.
· In India,
cloudbursts often occur during the monsoon season, when the southwesterly
monsoon winds bring copious amounts of moisture inland. · The moist air
that converges over land gets lifted as it encounters the hills. The moist air reaches an altitude and gets
saturated, and the water starts condensing out of the air, forming
clouds. · This is how
clouds usually form, but such an orographic
lifting together with a strong moisture convergence can lead to intense
cumulonimbus clouds taking in huge volumes of moisture that are dumped during
cloudbursts. · Tall cumulonimbus clouds can develop in about
half an hour as the moisture
updraft happens rapidly, at a pace of 60 to 120 km/hr. · A single-cell
cloud may last for an hour and dump all the rain in the last 20 to 30
minutes, while some of these clouds merge to form multi-cell storms and last
for several hours. · Cloudbursts occur mostly over the rugged terrain
of the Himalayas, Western Ghats, and northeastern hill states of India. · The heavy
spells of rain on the fragile steep slopes trigger landslides, debris flows,
and flash floods, causing large-scale destruction and loss of people and
property.
Recent Cloudburst Events
— On July 8, 2022,
flash floods occurred in the Lidder Valley en route to Amarnath Temple in
Jammu and Kashmir, taking the lives of several pilgrims.
— Himachal Pradesh
(2003), Ladakh (2010) and Uttarakhand (2013)
Conclusion:
Ground monitoring
stations can hardly capture the characteristics of cloudbursts due to their
highly localised and short occurrences. Hence, most of these events go
unreported due to the lack of monitoring mechanisms in the region, weakening
our ability to understand them from a complete perspective. |