Cyclones
The word 'cyclone' is derived from a Greek word meaning 'coil of snake'. In meteorological terms, cyclone is a low pressure from all sides. A cyclone may be elliptical, circular or 'V' shaped. Cyclones can be classified as tropical or temperate based on the location where they occur. The various impacts of cyclone are listed below:
In order to mitigate the effects of cyclones, a rehabilitation plan with geographical focus and prioritization of intervention should be prepared. The plan should contain measurable indicators like infrastructure, livelihood and habitat.
Floods
The different types of flood are:
In order to predict floods accurately, a long-time series of historical data that relates stream flows to measured past rainfall events is required.
Radar estimates of rainfall and general weather forecasting techniques are important components of good flood dorecasting.
The word 'cyclone' is derived from a Greek word meaning 'coil of snake'. In meteorological terms, cyclone is a low pressure from all sides. A cyclone may be elliptical, circular or 'V' shaped. Cyclones can be classified as tropical or temperate based on the location where they occur. The various impacts of cyclone are listed below:
- Storm surge causes
- Flooding in coastal areas
- Erosion of beach
- Loss of soil fertility and
- Damage to structures
- Winds
- Damage to structures
- Loss of power and communication
- Loss of life
- Agricultural loss and livestock losses
- Flooding in inland areas
- Land subsidence
- Contamination of water supply system
- Destruction of crops and livestock
In order to mitigate the effects of cyclones, a rehabilitation plan with geographical focus and prioritization of intervention should be prepared. The plan should contain measurable indicators like infrastructure, livelihood and habitat.
Floods
Floods are a common feature in India occurring in many areas. Floods are a natural phenomena.
Flood is a water related disaster. A flood occurs when the geomorphic equilibrium in the river system is disturbed due to intrinsic or extrinsic factors. or when the system crosses the geomorphic threshold.
- Flooding in the river bed due to aggradation of river bed (intrinsic threshold)
- Flooding in the river due to heavy rainfall (extrinsic threshold)
The different types of flood are:
- Flash floods
- River floods
- Coastal flood and
- Urban flood
- Slow-onset floods
- Rapid-onset floods and
- Flash floods
Floods can also be classified as:
- Natural
- Storm surge
- Tsunami
- Glacial melt
- Landslides
- Riverine, Estuarine and Marine floods
- Examples are bursting of landslide and blockades in the catchment areas of rivers
- Man-made
- Breach of dam / barrage / embankment
- Release from reservoir
- Urban flood
- Examples are breach of almatti and narayanpur dams in karnataka
- Silting of river bed
- Inadequate capacity within the banks
- River bank erosion
- Flow obstruction and change in river course
- Common floods in the main and tributary rivers
- Poor natural drainage
- Cyclones
- Retardation of flow and backwater flow
- Heavy rainfall
Factors influencing floods:
- Vegetation cover
- Climate
- Slopes
- Rainfall intensity and duration
- Land use
- Rock type
- Lakes and reservoirs
- Soil depth and type
- Human loss
- Property loss
- Affects the major roads
- Disrupts transportation services
- Spread of water-borne communicable services
- Disruption in electricity and communication services
- Social and economic disruption
- Pollution of air and water
In order to predict floods accurately, a long-time series of historical data that relates stream flows to measured past rainfall events is required.
Radar estimates of rainfall and general weather forecasting techniques are important components of good flood dorecasting.