Cyclones from Arabian Sea

Cyclone Vayu has changed course and has started moving away from the Indian coast towards Oman. Cyclone Vayu which was categorised as very severe was seen an outliner.

Why seen as an outliner?

• West coast of India sees much fewer cyclones than the East coast. Data suggests that the eastern coast witnesses four times more cyclones than the Arabian Sea side on an average.
• Only about25% of the cyclones that develop over the Arabian Sea approach the West coast like cyclone Vayu whereas about 58% of cyclones formed in the Bay of Bengal reach the coast.
• Even among those which make the landfall on the West coast, only a handful have been categorised as very severe in the last few decades. Cyclone Vayu is expected to be the strongest cyclone to hit the region since 1998.

Hence Cyclone Vayu is seen as an outliner.

Changing pattern of Arabian Sea Cyclones

Even though tropical cyclones are originated in the Arabian Sea, they generally do not reach a high intensity because of

• The dry air coming from the desert of the Arabian Peninsula (high humidity helps cyclones intensify).
• Wind patterns related to the monsoon.

Of late there has been an increase in the intensity of pre-monsoon Arabian Sea cyclones especially after 1979 because of the increase in air pollution. Air pollution has caused a decrease in the wind shear(sudden changes in wind velocity or direction or both) resulting in storms becoming stronger.