Classified as a severe cyclonic storm by the Indian Meteorological Department (IMD), Cyclone Phailin originated over east central Bay of Bengal and has since intensified moving north-westwards, 800 km southeast of Paradip (Odisha) and 870 km east-southeast of Visakhapatnam (Andhra Pradesh).
• It is all set to make landfall close to Gopalpur in Odisha at a wind speed of at least 205 kmph on Saturday.
• Satellite images showed the storm, in the Bay of Bengal, to be about half the size of India.
• Phailin means sapphire in the Thai language.
According to a London-based storm tracking service - Tropical Storm Risk - Phailin is a Category 4 cyclone, one notch below the most powerful Category 5 super storm like the one that hit Odisha in 1999 for 30 hours, killing almost 10,000 people.
Here's what the various categories mean:
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 caravans, 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, caravans destroyed, 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.
Techniques used to predict intensity of cyclones
• Satellite (Dvorak) techniques
• Radar techniques
Why 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.
• These newly selected names have two major differences from the rest of the world's tropical cyclone name rosters. One, the names by and large are not personal names. There are a few men's and women's names, but the majority are names of flowers, animals, birds, trees, or even foods, etc, while some are descriptive adjectives. Secondly, the names are not allotted in alphabetical order, but are arranged by contributing nation with the countries being alphabetised.
• 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.