2. Word "Cyclone" is derived from the Greek, word "Cyclos" meaning the
coils of a snake.
‘Cyclone’ is the term used globally to cover tropical weather systems in which winds
equal or exceed ‘gale force’ (minimum of 34 knot, i.e., 62 kmph).
These are intense low pressure areas of the earth atmosphere coupled system and
are extreme weather events of the tropics.
anti-clockwise direction in the Northern Hemisphere and in clockwise direction in the
Southern Hemisphere.
known as Hurricane in the Atlantic and Eastern Pacific, Typhoon in Western Pacific,
Willy-Willies in Australian,
Baguis in the Philippines.
3. The principal dangers of a cyclone :
Gales and strong winds
Torrential rain
Storm surges or high tidal waves
NAMING OF CYCLONE
Cyclones derive their names through a systematic procedure laid down by the World
Meteorological Organization (WMO)
United Nations Economic and Social Commission for Asia and the Pacific (ESCAP).
India Meteorological Department (IMD).
National disaster management authority (NMDA)
Eight north Indian Ocean countries - Bangladesh, India, the Maldives, Myanmar,
Oman, Pakistan, Sri Lanka and Thailand - have prepared a list of 64 names.
5. An air mass is a large body of air that has
similar temperature and moisture
properties throughout. The best source
regions for air masses are large flat areas
where air can be stagnant long enough to
take on the characteristics of the surface
below
Once the cyclone is fully developed, well-defined fronts
appear.
A front is defined as the transition zone between two air
masses of different density. Fronts extend not only in the
horizontal direction, but in the vertical as well
6. INDIAN SCINARIO
India has a coastline of about 7,516 km,
5,400 km along the mainland, 132 km in
Lakshadweep and 1,900 km in the Andaman
and Nicobar Islands.
Thirteen coastal states and Union
Territories (UTs) in the country are affected
by tropical cyclones. Four states (Tamil Nadu,
Andhra Pradesh, Orissa and West Bengal)
and one UT (Pondicherry) on the east coast
and one state (Gujarat) on the west coast
are more vulnerable to cyclone hazards.
8. Various Types of Cyclonic Disturbances formed in the Bay of Bengal Affecting the
East Coast of India between 1891 and 2000
9. CYCLONES PARAMETERS CONSIDERATION
To determine the degree of proneness the following parameters have been considered.
The composite score has been further been divided
into four categories like:
low (≤3),
moderate (>3 and ≤5),
high (>5 and ≤7) and
very high (>7)
10. By : NDMA(national disaster management authority)
11. Main Objectives of NCRMP
The National Cyclone Risk Management Project (NCRMP)
12. DESIGN GUIDELINES FOR BUILDINGS
i) The design to be carried out for 1.3 times the basic wind speed as recommended in the IS 875 - 1987 part 3.
The basic wind speed as per the code in most parts of the coastal zone is 50 m/s (180 km/hour) up to
10 m above ground level. Further, a number of corrections are to be applied based on the importance of the
structure (risk assessment), topography, size and shape of the building.
ii) The design will also be able to withstand seismic forces in regions which are additionally vulnerable to
earthquake hazard, such as Kandla, etc.
iii) The local community will be encouraged to construct houses which will be cyclone resistant
iv) Sloping RCC roofs (say 1 in 5 or 6 slope) will be used to provide quick rain water drainage and avoid any
seepage or leakage.
v) Minimum M30 Concrete grade (concrete having a characteristic strength of 30 N/mm2) and reinforcement steel
of Fe415 grade will be used in the construction. A design concrete mix as specified by IS Code 456
will be adopted.
vi) An extra cover of 5 mm beyond that specified in IS: 456 for the relevant exposure condition is to be provided
for steel reinforcement.
vii) The walls and all the RCC work will be plastered with cement mortar of 1:4. The outside plaster can be in two
coats. The building will have suitable cement plaster coating both outside and inside.
13. viii) The doors and windows will be of aluminium with anodized fixtures. The size and thickness of the doors and
windows must be of heavy gauge quality.
ix) All inserts and fittings will be of structural aluminium
x)The plinth height of 1.5 m will be used for stilt with the height varying from 2.5 m to 4.5 m if the storm surge
level is more than 1.5 m and less than 4.5 m. In all cases, the floor level will be at least 0.5 m above the possible
maximum surge level.
xi)The foundation will be taken to a depth equal to that of the surge level to avoid scouring, subject to a minimum
of 1.5 m.
xiii) The shelter will have a rectangular or polygonal plan depending on the functional aspect, with curved corners
for better aerodynamic features and the non-erosion of walls. A rectangular plan with curved corners is more
functional for many aspects.
20. implementations
The cyclone DM approach aims to institutionalise the implementation of initiatives and activities covering all
components of the DM cycle including prevention, preparedness, mitigation, relief, rehabilitation and recovery,
with a view to developing communities that are well informed, resilient and prepared to face cyclone-related
emergencies with minimal loss of life and property. Therefore, it will be the endeavour of the central
and state governments and local authorities, including ULBs and PRIs, to ensure implementation of these
guidelines.
BIS :Bureau of Indian Standards
MoUD & PA : Ministry of Urban Development and
Poverty Alleviation
SDMA : State Disaster Management Authorities
