Which one of the following causes is responsible for rainfall during winters in north-western part of India ?

Question

UnlockIAS · Accepted Answer

Correct — C, Western disturbances. Winter rainfall over north-western India (Punjab, Haryana, western Uttar Pradesh, Himachal Pradesh, Jammu & Kashmir and northern Rajasthan) is caused by western disturbances — extratropical cyclonic storms that originate over the Mediterranean/Caspian region and travel eastward, embedded in the subtropical westerly jet stream. They bring light-to-moderate winter rain to the plains and snowfall to the western Himalayas, and are vital for the rabi crop, especially wheat.

Why the other options are wrong — (a) Wrong — the retreating (north-east) monsoon brings October-December rain mainly to south-eastern India, notably the Tamil Nadu (Coromandel) coast, not winter rain to the north-west.  (b) Wrong — tropical cyclonic depressions form over the Bay of Bengal/Arabian Sea and affect the coasts in the monsoon and post-monsoon seasons; they are not the cause of NW-India winter rain.  (d) Wrong — the south-west monsoon is the June-September rainy season that delivers most of India's annual rainfall; it is a summer phenomenon, not a winter one.

Concept: Western disturbances are non-monsoonal, eastward-moving extratropical (temperate) cyclones that form over the Mediterranean/Caspian region and are steered across into north-west India by the mid-latitude westerlies and the subtropical westerly jet stream in winter. Over NW India between December and February they produce winter rain on the plains and snowfall in the western Himalayas.

State PCS 2021 Q10 — Geography PYQ with Answer

State PCS 2021 Q10 — Geography PYQ with Answer