The MeT office on Wednesday upgraded cyclone Titli to a ‘very severe cyclonic storm’ and warned that the wind speed may go up to 145 km per hour. The weather office added the landfall is expected on October 11 in Odisha and adjoining north Andhra Pradesh coasts between Gopalpur and Kalingapatnam.
Here’s how cyclones are categorised and what they mean:
Categories of Cyclones
Category 1: Wind and gales of 90-125 kph, negligible house damage, some damage to trees and crops.
Category 2: Destructive winds of 125-164 kph. Minor house damage, significant damage to trees, crops and vehicles, risk of power failure.
Category 3: Very destructive winds of 165-224 kph. Some roof and structural damage, some caravans destroyed, power failure likely.
Category 4: Very destructive winds of 225-279 kph. Significant roofing loss and structural damage, vehicles blown away, widespread power failures.
Category 5: Very destructive winds gusts of more than 280 kph. Extremely dangerous with widespread destruction.
The cyclone season
The country’s cyclone season runs from April to December, with severe storms often causing dozens of deaths, evacuations of tens of thousands of people from low-lying villages and wide damage to crops and property.
How are tropical cyclones named?
• Tropical cyclones are named to provide easy communication between forecasters and the general public regarding forecasts, watches, and warnings.
• The first use of a proper name for a tropical cyclone was by an Australian forecaster early in the 20th century. He gave tropical cyclone names after political figures he disliked.
• During World War II, tropical cyclones were informally given women’s names by US Army Air Corp and Navy meteorologists (after their girlfriends or wives) who were monitoring and forecasting tropical cyclones over the Pacific.
• From 1950 to 1952, tropical cyclones of the North Atlantic Ocean were identified by the phonetic alphabet (Able-Baker-Charlie-etc.), but in 1953 the US Weather Bureau switched to women’s names. In 1979, the World Meteorological Organization and the US National Weather Service (NWS) switched to a list of names that also included men’s names.
• The Northeast Pacific basin tropical cyclones were named using women’s names starting in 1959 for storms near Hawaii and in 1960 for the remainder of the Northeast Pacific basin. In 1978, both men’s and women’s names were utilised.
• The Northwest Pacific basin tropical cyclones were given women’s names officially starting in 1945 and men’s names were also included beginning in 1979. Beginning on 1 January 2000, tropical cyclones in the Northwest Pacific basin are being named from a new and very different list of names.
• The Southwest Indian Ocean tropical cyclones were first named during the 1960/1961 season.
• The Australian and South Pacific region (east of 90E, south of the equator) started giving women’s names to the storms in 1964 and both men’s and women’s names in 1974/1975.
• The North Indian Ocean region tropical cyclones are being named since October 2004.
Names reused every six years
• Atlantic and Pacific storm names are reused every six years, but are retired “if a storm is so deadly or costly that the future use of the name would be insensitive or confusing,” according to forecasters at the US National Hurricane Center in Miami.
• Hurricane Sandy was the 77th name to be retired from the Atlantic list since 1954. It will be replaced with “Sara” beginning in 2018, when the list from 2012 is repeated. Hurricane Sandy was the deadliest and most destructive hurricane of the 2012 Atlantic hurricane season that hit the US last year.
Not without controversy
Cyclone Mahasen, which hit in 2013 and was named by Sri Lanka, was changed to Viyaru after protests by nationalists and officials in Sri Lanka.
They said Mahasen was a king who had brought peace and prosperity to the island, and it was wrong to name a calamity after him.
First Published: Oct 10, 2018 11:27 IST
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