Disaster Management
Ankita Sengar
Cyclones
Cyclone refers to any inner spinning
storm that rotates around a low- pressure
centre. The low-pressure centre is also
referred to as the 'eye' of the storm.
Tropical Cyclone
Mesocyclone
Types of cyclone
? Tropical cyclones-most common in north
Indian ocean
? Hurricanes-most dangerous
? Polar cyclones
? Meso-cyclone-cyclone with vertical axis.
Cont.
? A tropical cyclone is the general term for violent circular
winds with torrential rains that originate in the tropics.
? Tropical cyclone is the storm system fuelled by the heat
released when moist air rises and the water vapour in it
condenses
? Favourable environmental conditions that must be in place
before a tropical cyclone can form: Warm ocean waters (at
least 80°F / 27°C).An atmosphere which cools fast with
height (potentially unstable).Moist air near the mid-level of
the troposphere (16,000 ft / 4,900 m).Generally a
minimum distance of at least 300miles (480 km) from the
equator. A pre-existing near-surface disturbance. Little
vertical wind shear between the surface and the upper
troposphere. (Vertical wind shear is the change in wind
speed with height.)
Cont.
? Hurricanes is the term when they occur in the
Atlantic Ocean
? They are called typhoons in the Pacific Ocean.
? They are called cyclones in the Indian Ocean.
Worst tropical Cyclones
? Coringa, India 1839 Bay of Bengal 300,000
? India 1833 Bay of Bengal 50,000
? India 1854 Bay of Bengal 50,000
? India 1935 Bay of Bengal 60,000
Cont.
India Stats
? The Indian subcontinent is one of the most
affected areas by cyclone in the world
? There are two definite peaks of tropical
cyclones in the North Indian Ocean. The first
peak is from May to June, and the other is
from mid-September to mid-December.
? six percent of the worldwide cyclones
? The destructive effect of cyclonic storms is
confined to coastal districts and the
maximum destruction being within 100 km
from the centre of the cyclones.
Cyclone management in
INDIA
Stages Warning Meaning
Issued 72 hours in advance, it discusses the likelihood of
Cyclone development of a cyclonic disturbance in the north Indian
Stage 1
Watch Ocean and the coastal region likely to experience adverse
weather.
Cyclone Issued 48 hours in advance of the commencement of adverse
Stage 2
Alert weather over the coastal areas.
Issued 24 hours in advance of the commencement of adverse
Cyclone
Stage 3 weather over the coastal areas. The location of landfall is
Warning
discussed at this stage.
Issued 12 hours in advance of the commencement of adverse
Landfall weather over the coastal areas. The track of the cyclone after
Stage 4
Outlook the landfall and the possible impact inland is discussed at this
stage.
India recent Cyclones
? Cyclone Amphan – 2020
? Cyclone Fani – 2019
? Cyclone Phethai – 2018
? Cyclone Titli - 2018
? Cyclone Ockhi – 2017
? Cyclone Vardah – 2016
? Cyclone Hudhud – 2014
