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III.  Overview of Natural Disasters

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1. Floods

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Among all the disasters that occur in the country, river floods are the most frequent and often the most devastating. While the area liable to floods is 40 million hectares, the average area affected by floods annually is about 8 million hectares.  The annual average cropped area affected is approximately 3.7 million hectares.  The average annual total damage to crop, houses and public utilities during the period 1953-97 was about Rs.9720.00 million, while the maximum damage was Rs. 46300.00 million in 1988.The average annual human lives is 1504, loss of livestock 96713 and damage to houses 11683 during this period. Information on extent of damage due to floods during 1981-1997 is given in Annexure-I

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Flood Hazard Map

 

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Water Map of India

Water Map

 

   

2. Droughts

.   Due to erratic behavior of monsoon, both low (less than 750 mm) and medium (750 - 1125 mm) rainfall regions, which constitute 68 per cent of the total areas, are vulnerable to periodical droughts.  The analysis of 100 years of rainfall behavior reveals that the frequency of occurrence of below normal rainfall in arid, semi-arid, and sub-humid areas is 54-57 per cent, while severe and rare droughts occur once every 8- 9 years in arid and semi-arid zones. In semi-arid and arid climatic zones, about 50 per cent of the severe droughts cover generally 76 percent of the area. In this region, rare droughts of most severe intensity occurred on an average once in 32 years and almost every third year was a drought year.  The impact of drought varies from year to year. The 1987 drought, which was one of the worst droughts of the century, with the overall rainfall deficiency of 19 per cent, affected 58-60 per cent of cropped area and a population of 285 million.

 

3. Cyclones

3.1 India has a long coastline of 8,000 kms, which is exposed to tropical cyclones originating from Bay of Bengal and Arabian Sea . . On an average, about five to six tropical cyclones form in the Bay of Bengal and Arabian Sea every year, out of which two to three may be severe .The east coastline of the country is more prone than the west as cyclones as about 80 percent of the total cyclones generated in the region hit here. There are two definite seasons of tropical cyclones in the North Indian Ocean .

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 Wind and Cyclone Hazard Map

 

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3.2   The impact of these cyclones is confined to the coastal districts, the maximum destruction being within 100 Km. from the center of the cyclones and on either side of the storm track. . Some of the severe cyclones occurred during 1990-1999 include: Andhra Pradesh, May 1990 (loss of 928 human life); Andhra Pradesh October,1996 (human life lost-1057): Gujarat , June ,1998( 1261 loss of human life) and Orissa, October,1999 ( 8913 loss of human life) 

 

3.3 Information on some severe cyclones in India since 1847 is at Annexure-II

 

 

4. Earthquakes

4.1 Earthquakes are considered to be one of the most dangerous and destructive natural hazards. The impact of this disaster is sudden with very little or no warning, making it just impossible to predict it or make preparations against damage and collapse of building and other man-made structures. India has a large part of its land area liable to wide range of probable maximum seismic intensities where shallow earthquakes of magnitudes of 5.0 or more on Richter Scale, have been known to occur in the historical past   or recorded in the last 100 years.  About 56% of the total areas in the country are vulnerable to seismic activities of varying intensity.  Most of the vulnerable area generally located in Himalayan and sub-Himalayan regions, Kutch and Andaman Nicobar Islands .

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4.2 Some of the recent major earthquakes occurred in the country are: 1991-Uttarkashi-Uttranchal Pradesh, 6.6 richter scale: 1993-Lathur – Maharashtra , 6.4; 1997 – Jabalpur -Madhya Pradesh, 6.0; 1999 Chamoli- Uttranchal Pradesh6.8; and 2001 Bhuja-Gujarat, 6.9 Richter scale.

4.3 List of some of major earthquakes occurred since 1819 is at Annexure -III

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Earthquake Hazard Map

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5. Landslides 

  

The landslides are simply defined as the mass movement of rock, debris or earth down a slope and have to include a broad range of motions whereby falling, sliding and flowing under the influence of gravity dislodges earth material. They often take place in conjunction with earthquakes, floods and volcanoes. The Himalayan mountain, the north-east hill ranges and the Western Ghats and the Nilgiris  experience considerable landslide activities of varying intensities. 

 

6. Avalanches

Avalanches constitute a major hazard in the higher reaches of the Himalayas . Heavy loss of life and property has been reported due to avalanches.  Parts of the Himalayas receive snowfall round the year and adventure sports are in abundance in such locations.  Severe snow avalanches are observed during and after snowfalls in Jammu & Kashmir, Himachal Pradesh and the Hills of Western Uttar Pradesh.  Major causes of the avalanches are: Inclination of slope where avalanche occurs; scale of slope, shape of slope, location (ridge line or toe of slope); orientation of slope; depth of snow -cover, depth of snowfall, wind velocity , atmospheric and snow temperatures etc .

 

7. Forest Fire 

Forest face many hazards but the most common hazard is forests fire. Forests fires are as old as the forest themselves. The forest fires are caused by natural causes and manmade causes. The most vulnerable stretches of the world are the youngest mountain ranges of Himalayas . The forests of Western Himalayas are more frequently vulnerable to forest fires as compared to those in Eastern Himalayas . In India, the hilly areas vulnerable to forest fires lie in the States Arunachal Pradesh, Assam, Himachal Pradesh, Jammu & Kashmir, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, Tripura and Uttranchal Pradesh. Forest fire incidents are not very uncommon. In the recent past, the fire in 1995 in the Uttranchal had destroyed more 375,000 hectares of forest wealth.

 

 

8. Pest Infestation

 Food losses due to pests, disease, wild animals, insects and weeds are considerable. It is estimated that 35% of world crop production is lost in spite of pesticide and other control programs. The primary pests are insects, disease and weeds.  Losses due to birds and wild animals are low compared to these.  Causes of pest infestation include temperature, monoculture of crops, and introduction of plants new locations, weather pattern and migration of pestfs species.

 

In India the locust infestation prone States are: Rajasthan, Gujarat , Punjab , Haryana, Andhra Pradesh, Karnataka, and Maharshtra. A desert area of over 200,000 sq.km covers the States of Rajasthan, Gujarat , Punjab and Haryana. Locusts caused substantial damage in the past. In recent years Indian experienced large-scale locust invasion in 1978. Again during July1993, the country experienced unprecedented level of locust invasion.  The swarming activity continued till October1993 and a total of 172 swarms entered the country.

 

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