Tropical storms are an area of low pressure with winds moving in a spiral around the calm central point called the eye of the storm. Winds are powerful and rainfall is heavy. They can last for days to weeks within the Tropical regions of our planet.
Hurricanes occur when these tropical storms develop wind speeds of over 74mph (miles per hour). They are known by many names, including hurricanes (North America), cyclones (India) and typhoons (Japan and East Asia). Tropical storms are defined by their wind speeds and the potential damage they can cause, using what is known as the Saffir Simpson scale, shown below. Many tropical storms form between the tropics, some develop into tropical depressions but not many actually develop into full blown hurricanes/cyclones/typhoons.
Wind speeds are used to decide what category of storm a tropical storm is, over 120Kph or 74 miles per hour is needed for a category 1 hurricane, over 250Kph or 155 miles per hour is the worst hurricane, a category 5 which would cause extreme damage.
As can be seen on the map, these storms all start within the Tropics over warm ocean waters. Their paths then take them outside of the tropics and they die out over time once they have made landfall. The most tropical storms can be found in the Asian Pacific.
The global location of tropical storms
How tropical storms form