Classification of natural disasters
Topic: Natural Hazards and Disaster Management in India · NCERT: Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management"
Meaning
NCERT (Class 11 Table 6.1) sorts natural disasters into four classes by where they start:
- Atmospheric (in the air): blizzards, thunderstorms, lightning, tornadoes, tropical cyclones, drought, hailstorms, frost, heat waves (the loo) and cold waves.
- Terrestrial (in the land): earthquakes, volcanoes, landslides, avalanches, subsidence (sinking ground) and soil erosion.
- Aquatic (in water): floods, tidal waves, storm surges and tsunamis.
- Biological (from living things): locusts, and diseases such as bird flu and dengue.
Grouping disasters this way helps planners know which agency watches each one and which warning system it needs.
Example
A Bay of Bengal cyclone hitting Odisha is an atmospheric disaster. The storm surge it pushes onto the coast is an aquatic disaster. So one event can set off disasters from two classes.
Don't confuse with
- Drought as terrestrial: this is a common exam trap. Drought is atmospheric because it starts with too little rain. Soil erosion and subsidence are the terrestrial ones.