The Philippines is particular vulnerable to typhoons because of the vast expanse of warm water acting as a birth place for storms and few pieces of land to slow them down.

Most typhoons (known as cyclones or hurricanes elsewhere) do not hit land at their peak when they reach land, but Haiyan did.

A typhoon is also called a hurricane or cyclone, depending where on the globe they form. The balmy tropical oceans propagates increased evaporation, and the condensation of that water vapor into clouds releases a lot of heat. The heat creates a large area of low pressure, typically transforming it into a tropical storm. This storm sucks in surrounding winds which begin spinning about themselves due to the Coriolis effect. The storm grows over days and weeks as more moisture and winds are propagated by the warm ocean waters.

Typhoons are essentially gigantic heat engines. The warm water feeds heat into the air above it, and that in turn imparts more energy to the winds rotating in the storm. The warmer the water and the larger the area the warm water occupies, the more energy the storm picks up and the faster the winds become. Hurricane season occurs when large swaths of the ocean thousands of miles across possess waters warm enough to trigger and sustain multiple typhoons.

2. Eye on the size
The eye of a typhoon or hurricane can be anywhere between 3.2km (2mi) across right up to 320km (200mi) in diameter.

3. Record breaker
To date Typhoon Tip in 1979 has been recorded as the largest ever typhoon, but once all the data has been examined Typhoon Haiyan might take its place.

4. Supersized storm
A typhoon only becomes a super-typhoon once surface winds of over 240km/h (150mph) have been sustained for more than a minute.

5. In the line of fire
Due to its location in the tropics, the Philippines is one of the most prone countries to typhoons, as well as other natural disasters like earthquakes because it is also in a tectonic danger zone – the Ring of Fire.