KALLAKKADAL
- GEOGRAPHY
News:
What is Kallakkadal,
which has flooded houses in Kerala’s coastal areas?
What's
in the news?
●
Recently, hundreds of houses have been
flooded in several coastal areas of Kerala due to high sea waves, also known as
swell waves.
Key
takeaways:
●
Such flooding events are called swell surge or Kallakkadal in
Malayalam.
Kallakkadal:
●
Kallakkadal is essentially coastal flooding during the pre-monsoon
(April-May) season by swell waves on the southwest coast of India.
Backdrop:
●
The term Kallakkadal, used by local
fishermen, is a combination of two Malayalam words, including Kallan and Kadal.
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Kallan means thief and Kadal means sea.
Meaning ocean that arrives as a thief.
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In 2012, the term was formally approved by the United Nations Educational, Scientific and
Cultural Organization (UNESCO).
Formation
of Kallakkadal:
●
Kallakkadal is a consequence of the strong winds in the southern part of the Indian
Ocean, where an ocean swell is generated.
●
These generated waves then travel north to
reach the coast in two/ three days.
Recent
Incidents of Kallakkadal:
●
The latest instance took place after a low
atmospheric pressure system moved over the region around March 25 from the
South Atlantic Ocean — 10,000 kilometres off the Indian coast.
●
The arrival of the pressure system
resulted in strong winds, which led to the formation of swell waves of up to 11
metres in height.
Challenges
of Kallakkadal:
●
Kallakkadal occurs without precursors or any kind of local wind activity and as a
result, it has been very difficult for the coastal population to get an advance
warning.
●
However, early warning systems like the
Swell Surge Forecast System give forewaring seven days in advance.
●
This system was launched by the Indian
National Centre for Ocean Information Services (INCOIS) in 2020.
Difference
Between Kallakkadal and Tsunami:
●
Definition:
Kallakkadal is a flash flood event that occurs without any noticeable change in
local winds. On the other hand, tsunami
is a series of enormous waves created by an underwater disturbance.
●
Cause:
Kallakkadal is caused by strong winds, while tsunamis are caused by earthquakes.
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Wave
Height: Tsunamis have a small wave height offshore.
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Wavelength:
While ocean waves have a wavelength of only 30 or 40 meters, Tsunamis have a
very long wavelength, often hundreds of kilometers long.