1. TROPICALCYCLONE
by
NARMADHA VENUGOPAL

2. CONTENTS
 DEFINITION
 CYCLONE ZONE MAP
 LIST OF CYCLONES THAT AFFECTED INDIA
 EFFECT OF CYCLONES
 PREVENTIVE MEASURES
 CYCLONE FORECASTING TECHNIQUE
 CYCLONE WARNING SYSTEM
 CASE STUDY

4. DEFINITION
■ A tropical cyclone is a storm system characterized by
a low pressure center and a numerous thunder storms
that produce strong winds and flooding rain.
■ A tropical cyclone feeds on heat released , when
moist air rises resulting in condensation of water
vapor contained in the moist air.
■ Other names – hurricane , typhoon, tropical storm,
tropical depression.

5. ■ TROPICAL CYCLONE – TROPICAL +CYCLONE
■ Tropical – geographic origin of systems
■ Cyclone - Storms cyclonic nature with anti clockwise
movement in northern hemisphere and clockwise
movement in southern hemisphere

6. CYCLONE ZONE MAP OF
INDIA
Source: NDMA(National Disaster Management authority)

7. LIST OF CYCLONES
THAT AFFECTED
TAMILNADUName Lowest
pressure (mbar)
Year Winds
(kmph)
BOB 09 998 1991 85
BOB 06 994 1992 85
BOB 03 968 1993 175
08B 967 1996 120
BOB 05 958 2000 190
Fanoos 998 2005 85
Nisha 996 2008 85
Jal 986 2010 100

8. Thane 972 2011 140
Nilam 992 2012 85
Madi 986 2013 120
Roanu 983 2016 85
Kyant 997 2016 85
Nada 1000 2016 75
Vardah 982 2016 130
Ockhi 975 2017 155

9. EFFECT OF CYCLONES
ON BUILDINGS
■ Uprooted trees may fall on buildings and cause
damage.
■ Roofs and lintels may get damaged due to the force of
the wind.
■ Windows, parapets, fences and compound wall can
get damaged if they are not firmly fixed.

10. ■ Cyclones can affects us in other ways also;
electric cables and transmission towers can
be damaged causing immense hardship to people.
Live electricity wire on the road can prove to be a
death trap to people walking on the road sign post on
the roads can be damaged.

13. PREVENTIVE MEASURES
Here we are going to see the ten key principles of
cyclone resistant construction;
■ Choose the location carefully to avoid the full force of
wind or flood.
■ Use building layout , with a simple regular shape to
avoid the concentration of pressure.
■ Build the roof at an angle 30 to 45 degree to prevent it
being lifted off by the wind.

14. ■ Avoid wide roof overhangs; separate the verandah
structure from the house.
■ Make sure the foundations ,walls and roof structure
are all firmly fixed together.
■ Reinforce the bracings in the structure; strengthen
walls and joints/junctions to increase stiffness.
■ Make sure that the roof covering is firmly attached to
the roof structure to prevent it from lifting.

15. ■ Use doors and shutters that can be closed.
■ Plant trees around the house as wind breaks and
reduce flow of water, but not too close.

17. CYCLONE FORECASTING
TECHNIQUE

19. CYCLONE WARNING
SYSTEM

21. CASE STUDY ( VARDAH
CYCLONE)
■ VARDAH – dec,2016.
■ Originated in dec,3 and crossed Chennai in dec.12,
2016.
■ Originated from Andaman and Nicobar island
IMPACT IN CHENNAI
■ 16,000 were evacuated from low lying areas.
■ Claimed 18 lives
■ One lakh of trees were uprooted

22. ■ 10,000 electric poles were mangled and 800
transformers were damaged.
■ 77 cows were found afloat in a lake of kancheepuram.
■ 224 roads were blocked.
■ 24 huts were completely destroyed.
■ 10 were died due to events related to this cyclone.
■ The cost required by the government for the rescue
aftermath the cyclone were found to be 5.7 billion
USD.