TROPICAL
CYCLONES - GEOGRAPHY
News: Hurricane Idalia hits Florida,
flooding streets, snapping trees and cutting power
What's
in the news?
● Hurricane
Idalia tore into Florida at the speed of a fast-moving train, splitting trees
in half, ripping roofs off hotels and turning small cars into boats before
sweeping into Georgia as a still-powerful storm that flooded roadways and sent
residents running for higher ground.
Cyclones:
● Cyclones
are a type of low-pressure environment with
rapid inward air circulation.
● In
the Northern Hemisphere, air flows counter clockwise, while in the Southern
Hemisphere, it circulates clockwise.
Tropical
Cyclones:
● The
term ‘Tropical Cyclone’ is used by the World Meteorological Organization to
describe weather systems with winds greater than ‘Gale Force’ (minimum of 63 km per hour).
● Tropical
cyclones are formed in the region between the Tropics of Capricorn and Cancer.
● They
are large-scale weather systems that form over tropical or subtropical oceans
and coalesce into surface wind circulation.
● Tropical
cyclones are one of the world’s most destructive
natural disasters.
Favourable
Conditions for the Formation of Tropical Cyclone:
● A
large area of water surface with a temperature
above 27° C
● The
Coriolis force is strong enough to
form a cyclonic vortex.
● Variations in the vertical wind speed
are minor.
● A
weak low-pressure area or low-level
cyclonic circulation already exists.
● Above
the sea level system, there should be a higher
divergence.
Local
Names:
● North
Atlantic (including Caribbean and Gulf of Mexico): Hurricanes
● Eastern
and Central North Pacific: Hurricanes
● Western
Northern Pacific: Typhoons
● Arabian
Sea/Northern Indian Ocean: Tropical Cyclones
● South
Indian Ocean: Tropical Cyclones/Willy-Willy for southwest Australia
● Coral
Sea/South Pacific: Tropical Cyclone.