What is landfall?
- Landfall is the event of a storm or waterspout moving over land after being over water.
- A tropical cyclone is classified as making landfall when the center of the storm moves across the coast; in strong tropical cyclones this is when the eye moves over land.
Reason for cyclone development in the Bay of Bengal
- The Bay of Bengal is lying adjacent to the northwest Pacific, which is one of the world’s most active basins for typhoons.
- The region receives the remnants of major landfalls in the Philippines, China and South Asia.
- From these places come low-pressure systems that develop into a monsoon depression or a cyclone.
Why these cyclones hit mostly in October ?
- The reason that cyclones such as Titli, Phailin (2013) and Hudhud (2014) typically strike in October is that wind shear (the difference within wind speeds and direction at two different levels) is low during this time.
- Low wind shear, when combined with surface sea temperatures greater than 26°C, raises the likelihood of cyclones.
- In monsoon season, cyclones are rare because of high wind shear.
Why it was hard to predict the landfall of Cyclone Titli?
- The prediction is difficult because of budgetary and meteorological factors.
- In the Atlantic basin, the US has dedicated aircraft that fly directly into the clouds to study moisture levels and gather various data on cyclone profile.
- For Indian cyclones developing over the ocean, scientists have to largely rely on satellite images (a top view) that reveals little data on moisture content and intensity.
- Indian scientists get a more detailed picture only when a cyclone is 300-400 km from the coast, which reduces preparation time; Cyclone Titli was additionally hard to read because it turned into a recurving cyclone (it changed direction).
- India acquires storm prediction models from the US and Europe but lacks the resources to upgrade the models regularly.
How evacuation is done?
Researchers classify evacuation exercises as preventive, vertical, and shelter-in-place.
- In preventive (or horizontal) evacuation, the impact area is meant to be completely evacuated, but this is a measure rarely taken in India because of poor roads and inadequate public transportation.
- Shelter-in-place evacuation involves fortification of existing houses and community buildings, which again required financial resources.
- In vertical evacuation, people are directed to specially designed buildings within the impact area. This strategy was largely followed during Cyclone Titli.
Few Important Facts
- During Titli, Hudhud or Phailin, lives were saved because, unlike the 1999 Supercyclone, there was no storm surge (A storm surge is an abnormal rise of water generated by a storm).
How are cyclones named?
- In September 2004, an international panel on tropical cyclones decided that countries from the region would each put in names, which would be assigned to storms in the Bay of Bengal and Arabian Sea.
- Eight countries — India, Pakistan, Bangladesh, Maldives, Myanmar, Oman, Sri Lanka and Thailand – participated and came up with a list of 64 names.
- In the event of a storm, the Regional Specialized Meteorological Centre, New Delhi, selects a name from the list.
Why it is necessary to name cyclones?
- The purpose of the move was also to make it easier for “people easily to understand and remember the tropical cyclone/hurricane in a region, thus to facilitate disaster risk awareness, preparedness, management and reduction.