Cyclone Asna forms over Kutch; heavy rain batters Gujarat

Context: Cyclone Asna has formed over the Kutch coast in Gujarat and
adjoining areas of Pakistan, the India Meteorological Department (IMD) said on Friday.
The cyclonic storm — a rare land-originating one in August and headed to the
Arabian Sea — are expected to move further away from the western coast in the
next 48 hours.

Occurrence of cyclones in
India

·       India has a
bi-annual
cyclone season that occurs between March to May and October to December.
But on rare occasions, cyclones do occur in June and September months.

·       Typically, tropical
cyclones in the North Indian Ocean region (Bay of Bengal and
Arabian Sea) develop during the pre-monsoon
(April to June) and post-monsoon (October to December) periods.

·       May-June
and October-November are known to produce cyclones of severe intensity that
affect the Indian coasts.

·       Classification:
The IMD classifies cyclones on the basis of the Maximum
Sustained Surface Wind Speed (MSW) they generate. The cyclones
are classified as severe (MSW of 48-63 knots), very severe (MSW of 64-89
knots), extremely severe (MSW of 90-119 knots) and super cyclonic storm (MSW of
120 knots or more). One knot is equal to 1.8 kmph (kilometres per hour).

Tropical Cyclones

·      
A tropical cyclone
is an intense circular storm that originates over warm tropical oceans and is
characterized by low atmospheric pressure, high winds, and heavy rain.

·      
A characteristic feature of tropical cyclones is the eye, a
central region of clear skies, warm temperatures, and low atmospheric pressure.

·       Storms of
this type are called hurricanes in the North Atlantic and eastern Pacific and typhoons
in South-east Asia and China. They are called tropical
cyclones in the southwest Pacific and Indian Ocean region and Willy-willies
in north-western Australia.

·      
Storms rotate counter clockwise in
the northern hemisphere and clockwise in the southern
hemisphere.