DISTURBED

After an unusually dry and hot winter season, India faces an imminent low yield of rabi crops. The reason for this year's abnormal winter, the third in a row, lies in the changing character of the Western Disturbances. The frequency and intensity of the storm systems, which bring winter rains to the northern plains and snowfall in the Himalayas, are decreasing

- AKSHIT SANGOMLA

India has not experienced a normal winter in three years. The second wettest season in the country after the monsoons has remained unusually dry and hot. In this winter, for instance, the country experienced its hottest ever December, as per the India Meteorological Department (imd). The northwest region, which receives almost 30 per cent of its annual rainfall in the season, saw 83 per cent rainfall deficit. Then, after a near-normal January, February broke all records to become the hottest since 1901. The northwest region saw 76 per cent deficit rainfall.

The reason for the abnormal winter seasons since 2020-21 lies in the changing character of the Western Disturbances, a series of cyclonic storms that originate in the Mediterranean region, and travel over 9,000 km to bring winter rains to northwest India. The low-pressure storm systems help farmers in India grow their rabi crop, bring snow to the Himalayas and maintain the flow of the northern rivers. They reach the country riding on a wind system called the subtropical westerly jet stream that circles the Earth throughout the year.

During its journey, a Western Disturbance collects moisture from the Mediterranean Sea, Black Sea and Caspian Sea and traverses over Iran and Afghanistan before hitting the western Himalayas. Strong Western Disturbances reach the central and eastern Himalayas and cause rain and snow in Nepal and northeast India.

The last time the storm systems visited the country in all their glory was in 2019. Since then, their arrival has either been delayed or weakened. On an average, India receives four to six intense Western Disturbances a month between December and March, or 16 to 24 such events in the entire period, as per the "Western Disturbances: A Review", published in