Cyclone, hurricane or typhoon?

A woman holding an umbrella during heavy rainfall outside a temporary evacuation centre ahead of Typhoon Mangkhut's arrival in Tuguegarao, the Philippines, on Sept 14, 2018.
A woman holding an umbrella during heavy rainfall outside a temporary evacuation centre ahead of Typhoon Mangkhut's arrival in Tuguegarao, the Philippines, on Sept 14, 2018. PHOTO: BLOOMBERG

There is no difference between a typhoon, hurricane and cyclone. The name depends only on where a storm is formed.

The storms are created by the same processes, such as warm ocean surface temperatures, favourable wind conditions and other factors.

The National Oceanic and Atmospheric Administration (NOAA) in the United States notes that a tropical cyclone is a generic term used by meteorologists to describe a rotating, organised system of clouds and thunderstorms that originates over tropical or subtropical waters.

Once a tropical cyclone reaches maximum sustained winds of 119kmh or higher, it is then classified as a hurricane, typhoon or tropical cyclone, depending on where the storm originates in the world.

In the North Atlantic, central North Pacific and eastern North Pacific, the term hurricane is used, the NOAA says. In the North-west Pacific, the same type of storm is called a typhoon, while in the South Pacific and Indian Ocean, the generic term tropical cyclone is used.

The power of the storm is measured by wind speed, with Category 1 the lowest level and Category 5 the highest. A Category 5 storm has winds of 251kmh or higher.

Most tropical cyclones tend to occur at certain times of the year, depending on the location.

For example, the Atlantic hurricane season officially starts on June 1 and ends on Nov 30, with peak activity usually from mid-August to late October, the US National Hurricane Centre says. But hurricanes can also form outside the official season.

In the North-west Pacific, typhoons can occur at any time of the year, but with a peak usually from May to October. In the Philippines, it can be later. Some of the deadliest storms have hit between September and December.

A version of this article appeared in the print edition of The Straits Times on September 15, 2018, with the headline 'Cyclone, hurricane or typhoon?'. Print Edition | Subscribe