21EE753 Disaster management module -1 presentation

disaster management

1. Cyclone monitoring and mitigation group will consist of: (a) representatives of the States vulnerable to cyclones, (b) the IMD (India Meteorological Department) (c) National Remote sensing Centre (NRSC) and (d) Indian Space Research Organisation (ISRO).

2. M inistry

3. The standard operating procedures (SOPs) of cyclone disaster management plan are: 1. Disaster preparedness- Iongterm , like construction of shelter belts, cyclone shelters, education etc. 2. Disaster preparedness-just before the event, like alerting the people, storing food, water, machinary etc. 3. Action after receipt of warning - like evacuation of people from low-lying vulnerable areas which are likely to be affected, cancelling the leave of officials and ask them to proceed to their assigned work etc.

4. 4. Rescue operations before impact of cyclone. 5. Actions during impact phase of cyclone. 6. Rescue operations after impact of cyclone. 7. Relief operations after disaster (that is after dewarning of cyclone) 8. Rehabilitation operation 9. Reconstruction operation.

5. Disaster Preparedness Involves (i) Understanding the hazards associated with the type of event - like cyclone,flood , drought, earthquake etc. (ii) Understanding the ways how the type of event inflicts losses. In case of cyclone the losses occur due to heavy rains, strong winds, storm surges. (iii) Vulnerability or susceptibility. In case of cyclone low lying coastal areas are susceptible to inundation and wind fury, which inflicts damage to life and property like assets (Government and private), roads, bunds of tanks and rivers, uproots or damages trees, telegraphs and electric lines etc. (iv) Vulnerability reduction. Actions and measures that reduces vulnerability. In case of floods and cyclones strengthening of bunds, coastal flood embankments, shelter belts, wind breakers etc.

6. Cyclone and their Hazard Potential Tropical cyclones are the most destructive phenomena of atmospheric nature. They are foremost in their violence, destruction and duration. They generallyform over the sea, strike the coastal areas with their ferocity of winds, torrentialrains and inundate the area with storm surges. Compare with other natural disasters, an earthquake short lived (one or twominutes ) but cause much more devastation to life and property. Tornadoes are the most violent storms on earth but they are small in size and cause destruction in their narrow path for a short period. Extra tropical cyclones of winter are the largest phenomena of the atmosphere but they are very mild as compared to tropical cyclones. It was estimated that a normal cyclone precipitates water about 2 giga tons (2 x109 tons) in an hour and dissipates about 36 x 1010 kwh of kinetic energy. A moderate cyclone releases large amounts of energy, of which about 3% is the form of wind and wave energy. This energy is sufficient for all the needs of100-150 million people for a year.

7. cyclonic storm can be divided horizontally at surface level into four The central area (radius 20 to 50 km) with calm or light winds and generally clear sky, is called the Eye of the cyclone. The adjacent ring shaped area (ring width 10 to 20 km) with virtually overcast sky , towering cumulus and cumulonimbus clouds is called Wall-cloud Region . The third region of ring shaped area, radius extending upto 80 km from the centre , with strong hurricane winds (speed 118 kmph or more) is called a belt ofhurricane winds. The fourth , last region extending 200 to 500 km radius from the centre is calledouter ring region .

8. Statistics of Cyclonic Storms Over Indian Seas Studies of past historical cyclone data indicate that about 85% of depressions intensify into cyclonic storms with in 48 hours of their formation and within 12 to 24 hrs on 40% of the occasions. Cyclonic storms attain severe intensity within 36 hours on 75% of the occasions. More than 50% of cyclonic disturbances that form in the Bay of Bengal in the months of March, April, May, November and December intensify into cyclonic storms .

9. Movement of Cyclones in Indian seas Prediction of the movement of a cyclone is a very difficult job because it is erratic . However the past data of more than 100 years reveal the climaticmovement . The number of cyclones that cross or accost or skirt the east coast of Srilanka , Tamilnadu , Andhra Pradesh and Bangladesh is highest during October, November , December While that affect Orissa, West Bengal, Arakan coasts is maximum during monsoon (June, September) months and March, April, May. Most of the cyclonic storms (about 65%) form in the months of April, May and in October , November and December. During January, February and March cyclones do not form in Arabian sea, while in Bay of Bengal they are a few and farb etween . In these months they originate between lat 5oN and 8 oN , move in a westerly or northwesterly direction and hit the coast of north Tamilnadu and east coast of Srilanka . During April, May they form between lat 8 oN and 15 oN , move initially in a northwesterly or northerly direction and then recurve . In Bay of Bengal the whole east coast of India, coastal areas of Bangladesh and Arakan coast of Myanmar are prone to the incidence of cyclones. Arabian sea, they move towards the coast of Arabia. A few move in northerly direction towards Maharastra , Gujarat coasts.

10. Arabian sea, they move towards the coast of Arabia. A few move in northerly direction towards Maharastra , Gujarat coasts. During June to September (monsoon months) there will mostly be monsoon depressions and rarely cyclonic storms. During June, in Bay of Bengal, they originate between lat 16 oN and 21 oN and west of long 92°E, move in a northwesterly direction, cross coast and weaken. During July, August, in Bay of Bengal, they originate between lat 16 oN 2 I oN and west of long 92°E, move in a northwesterly or west north-westerly direction and cross coast between the zone of lat 20 oN -25oN. In Arabian sea there is abrupt fall from June to almost nil in July, August, September . During September Bay storms originate north of lat 15 oN and west of long 900 E, move initially in west or northwesterly direction, later recurvetowards north-north-east.

11. Storm surges

12. Storm surge heights