The formation and structure of tropical storms

• Rising air draws huge quantities of evaporated water vapor up from the ocean surface which cools and condenses to form towering thunderstorm clouds
• Condensation releases heat which powers the storm and draws up yet more water vapour
• Multiple localised thunderstorms join (coalesce) to form a gaint rotating storm
• Coriolis forces spin the storm at over 120 km/h creating a vast cloud spiral
• Prevailing winds drift the storm over the ocean surface like a spinning top, gathering strength as it picks up more and more heat energy
• On reaching land, the energy supply (evaporated water) is cut off and the storm weakens
• The centre is the eye - a column of rapidly sinking cool air where conditions are relatively calm and there are no clouds

  
• At the outer edge of the eye is the eye wall - the most severe conditions with very strong winds and torrential rainfall

  
• Cumulonimbus clouds swirling around beyond the eye wall bring additional bands of rain

  
• Tropical storms associated with extremely strong winds - often gusting in excess of 300km/h. But tropical storms move over the ocean slowly, which accounts for the very high rainfall totals that can exceed 400mm in a day (causing floods and landslides)
• Low-lying coastal areas can be inundated by storm surges (a change in sea level that is caused by a storm) up to 3 m high, driven onshore by the strong winds