Unlike typical cyclones that form over warm ocean waters, Asna originated as a deep depression over land in Gujrat and poised to intensify into a tropical cyclone over the Arabian Sea.
- According to IMD, only on three occasions (1976, 1964, and 1944), cyclones originated over mainland India in August and gathered strength as they entered the Arabian Sea.
- Possible reasons: Unusual monsoon wind system, moisture from the Arabian Sea and soil moisture from the lands, warming of Indian Ocean, etc.
Tropical Cyclones
- It is a rapidly rotating storm that begins over tropical oceans.
- Cyclones are classified as extratropical cyclones (temperate cyclones); and tropical cyclones.
- Known as typhoons (China Sea & Pacific Ocean); hurricanes (Caribbean Sea & Atlantic Ocean); tornadoes (West Africa & southern USA); & willy-willies (Australia).
In India
- India is exposed to nearly 10 % of the world’s tropical cyclones, which occur in May-June and October-November.
- More cyclones occur in the Bay of Bengal than Arabian Sea and the ratio is approximately 4:1.
- However, cyclones are becoming more frequent on the western coast due to climate crisis and the warming of the Arabian Sea.