Cyclone, hurricane, typhoon: different names, same phenomenon

PARIS, France – They may have different names according to the region they hit, but typhoons, hurricanes and cyclones are all violent tropical storms that can generate 10 times as much energy as the Hiroshima atomic bomb.

The typhoon that devastated the Philippines, wiping out entire towns with a death toll that could soar well over 10,000, is the Asian term for a low-pressure system that is called a hurricane in the Atlantic and northeast Pacific and a cyclone in the South Pacific and Indian Ocean.

But meteorologists use the term “tropical cyclone” when talking generally about these immensely powerful natural phenomena, which are divided into five categories according to the maximum sustained wind force and the scale of the potential damage they can inflict.

Super Typhoon Haiyan (Philippine codename Yolanda), which is now heading towards Vietnam, was a category 5 typhoon – the highest level – when it hit the Philippines, with maximum sustained winds estimated at 315 kilometers (196 miles) an hour, and gusts reaching 380 km/h, according to Japan’s meteorological agency.

The winds are reported to be the strongest ever measured, and Haiyan could wrest the title of most powerful cyclone on record from Super Typhoon Tip, which ravaged Japan in 1979.

The Philippines endures a seemingly never-ending onslaught of deadly typhoons, earthquakes, volcano eruptions and other natural disasters.

Every year, some 20 super storms or typhoons hit the country, of the 80 or so that develop above tropical waters annually.

Cyclones are formed from simple thunderstorms at certain times of the year when the sea temperature is more than 26ºC (79ºF) down to a depth of 60 meters (200 feet).

Sucking up vast quantities of water, they often produce torrential rains and flooding resulting in major loss of life and property damage.

They also trigger large swells that move faster than the cyclone and are sometimes spotted up to 1,000 km ahead of the powerful storm. The sea level can rise several meters.

These powerful weather formations can measure between 500 and 1,000 km in diameter and have a relatively calm “eye” at the center.

They weaken rapidly when they travel over land or colder ocean waters.

Cyclones are closely monitored by satellites, and specialized centers around the world – in Miami, Tokyo, Honolulu and New Delhi – track the super storms’ trajectories under the coordination of the World Meteorological Organization. – Rappler.com

Get the latest info on the status of areas affected by typhoon Yolanda (international codename: Haiyan).

Help the victims of Yolanda. Visit Rappler’s list of ongoing relief operations in your area. Tell us about your relief and recovery initiatives, email move.ph@rappler.com or tweet us @moveph.

Visit rappler.com/typhoon-yolanda for the latest updates on Typhoon Yolanda.

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• #ReliefPH: Victims of Typhoon Yolanda need your help
• Iloilo under state of calamity
• President’s ‘pork,’ savings to fund Yolanda relief efforts
• Tacloban hospital faces medicine shortage
• Land route from Manila to Tacloban now passable – Roxas
• Worried Pinoys use social media to find loved ones
• Tacloban Diary: I saw death, I fear anarchy
• TIMELINE: Super Typhoon Yolanda
• WRAP: Hundreds feared dead as Yolanda exits PH