India 2020: India and Bangladesh evacuated around half a million people out of the way of the most powerful storm Amphan in a decade ahead of its landfall on Wednesday amid fears of heavy damage to houses and crops and disruption of road, rail and power links.
Approaching from the Bay of Bengal, Amphan is expected to make the landfall between West Bengal and Bangladesh with winds gusting up to 185 kmph. The wind speed packed in by Cyclone Amphan is equivalent of a category 5 hurricane.
The cyclone will generate sea waves as high as a two-storey house that could swamp mud dwellings along the coast, uproot communication towers and inundate roads and rail tracks.
Bangladesh authorities fear that Amphan will be the most powerful storm front since Cyclone Sidr devastated the country in 2007, killing about 3,500 people and causing billions of dollars in damage.
Here is a look at what makes cyclones deadly:
• Cyclones are low-pressure systems that form over warm tropical waters, with gale force winds near the centre. The winds can extend hundreds of kilometres (miles) from the eye of the storm. Sucking up vast quantities of water, they often produce torrential rains and flooding resulting in major loss of life and property damage. Tropical cyclones (hurricanes) are the most powerful weather events on Earth, according to NASA.
• Cyclones can unleash catastrophic storm surges – tsunami-like flooding – when they make landfall. The large swells move faster than the cyclone and are sometimes spotted up to 1,000 kilometres ahead of a major storm. The surge can extend for dozens of kilometres inland.
• Experts say that one of the reasons for cyclones to be so devastating is the favourable conditions in Bay of Bengal, like high sea surface temperatures. The tropical cyclone season in the Bay of Bengal and neighbouring Arabian Sea has two peaks around May and November, according to the World Meteorological Organisation. The cyclones can form in the western Pacific Ocean and travel in a northwest direction before arriving in the Bay of Bengal. Some reach the southeastern coast of India but others divert northeast and move up to West Bengal and Odisha states.
• Studies suggest a warming climate could bring more destructive cyclones as there would be extra heat in the oceans and atmosphere, although such systems could also become less frequent. Rising sea levels could boost storm surges from cyclones, making them even more deadly and destructive.