Question: What is the very first thing to form a hurricane or typhoon

Dave Sproson answered on 15 Jun 2011:

Hi coconut,

Hurricanes and typhoons are basically exactly the same thing — but hurricanes form over the Atlantic ocean and typhoons over the Pacific ocean. They’re both examples of ‘tropical cyclones’.

They start to form when the surface of the ocean is very warm, and lots of water can evaporate from the surface and move up high in the atmosphere, where it re-condenses to form clouds. When the clouds form, the water gives up some of its heat to the atmosphere, which is the main energy source for the cyclone. Eventually the atmosphere starts to rotate (due to the rotation of the earth) and you have yourself the beginnings of a hurricane (or typhoon).

The storm can continue to get stronger as long as this energy source is available – i.e. as long as it is over a very warm ocean. As soon as hurricanes/typhoons move over land, their energy supply is cut off and they die quite quickly, which is why generally only coastal cities or islands are at risk from these storms.