india

Updated: Feb 04, 2019 23:42 IST

Jammu and Kashmir, Uttarakhand and Himachal Pradesh are likely to receive “heavy to very heavy snowfall” later this week, the India Meteorological Department (IMD) said on Monday, issuing a red-category warning for civic agencies and people in affected areas to be cautious.

The warning is due to a new “intense western disturbance” approaching the region, the IMD said, referring to winds from over the Arabian Sea region that bring in moisture and cause rain and snow.

While snowfall in the upper Himalayan region in February and March is not uncommon, the influence of the western disturbances is unusually prolonged this time due to another factor: the Siberian High weather pattern — a collection of cold, dry air that accumulates around northeastern Siberia in the winter months.

“The arctic air outflow is dominating towards the south causing freezing temperatures in North America and parts of Europe. Further, mid-level westerlies are weakening, which causes an increased outflow from the Siberian High. This cold air is pushing towards tropical Asia including north India,” said Charan Singh, scientist at IMD, explaining why the winter chill has lasted longer this year.

Uttarakhand has received the highest snowfall in five years this January, while Jammu and Kashmir region has received 47% excess rainfall.

IMD scientists said these figures will change vastly by the end of February if there are more western disturbances.

Till January 31 this year, there have been eight western disturbances (WDs) influencing snowfall and rainfall pattern and temperature in north India.

This week’s will western disturbance will make it a total of nine, as against the normal of 5-6 each year.

“The mid-latitude westerlies are weaker than normal for more than a month now across the globe due to weakening of polar vortex. This causes westerly waves to form which leads to formation of WDs. These WDs are also affecting northern India and bringing colder air from the north,” said DS Pai, head of climate research at Pune.

Krishna Achuta Rao, climate scientist from IIT Delhi, described the number of WDs as “quite high” but said the link between polar vortex and WDs need to be understood better.

As a result of the snow in the four states, all of north-western India will experience the chill. Hailstorm and rain is expected in Delhi and NCR during February 5 and 7.

The effects will stretch to Punjab, Haryana, Chandigarh, Delhi, Uttar Pradesh and as far as north Madhya Pradesh, north Chhattisgarh, Jharkhand, Bihar and Sub-Himalayan West Bengal and Sikkim.

The national capital has seen the longest cold spell in at least 13 years, and, according to the World Meteorological Organization, this has been in keeping with a global weather anomaly.

The month of January, the WMO said, has been a period of extremes, with unusually cold temperatures in the northern hemisphere and warm temperatures in the southern.