Cyclones

Cyclones

Subject – Geography

Context – Nearly 6,800 people lost their lives in the country over the past three years due to hydro­meteorological calamities such as flash floods, landslips and cyclones, and West Bengal has recorded the highest deaths among all States.

Concept –

• A tropical cyclone is an intense circular storm that originates over warm tropical oceans and is characterized by low atmospheric pressure, high winds, and heavy rain.
• A characteristic feature of tropical cyclones is the eye, a central region of clear skies, warm temperatures, and low atmospheric pressure.
• Storms of this type are called hurricanes in the North Atlantic and eastern Pacific and typhoons in South-East Asia and China. They are called tropical cyclones in the southwest Pacific and Indian Ocean region and Willy-willies in north-western
• Storms rotate counter-clockwise in the northern hemisphere and clockwise in the southern

• The conditions favourable for the formation and intensification of tropical storms are:
  • Large sea surface with temperature higher than 27° C.
  • Presence of the Coriolis force.
  • Small variations in the vertical wind speed.
  • A pre-existing weak low-pressure area or low-level-cyclonic circulation.
  • Upper divergence above the sea level system.