Uttarakhand to Himachal to J&K, why this winter feels snowless

Experts say that winters in the Himalayan states like Uttarakhand have been getting increasingly dry over the past decade. “During the last ten years, there have been four occasions when Uttarakhand received very little rain in January. This indicates that this trend is becoming common,” IMD Dehradun director C S Tomar said.

The 2024-25 winter season had seen rainfall deficiency of 96 per cent in the northwestern region. Studies have shown a marginal declining trend in the winter season rainfall over some pockets of north India.

During winters, the north and northwest India regions normally experience light to moderate intensity rainfall mainly triggered by the passing streams of western disturbances. This precipitation is particularly vital for the rabi crops cultivated along the plains and supported by irrigation. In the higher altitudes, snow or rainfall is key for the recharge of the groundwater aquifers.

In December and January, streams of passing western disturbances normally interact with moisture-laden easterly or westerly winds coming in from either the Bay of Bengal or the Arabian Sea. This creates a wind confluence that happens normally over the Himalayas. It results in precipitation in the form of snow or rainfall.

But this year, the western disturbances have not been strong enough to trigger a rainfall event. In December, eight western disturbance streams (against normal of six) crossed northern-most Indian region, but produced little rains.

“The western disturbances currently have little moisture, and the trough, the region of low pressure, is shallow, impeding its ability to lift moisture. The propagation is northward at a higher latitude, which explains bits of precipitation in Kashmir and parts of Himachal Pradesh, because it intersects those regions first and can release moisture there, but not in Uttarakhand, which lies eastward. Another reason could be that when the system approaches the Indian subcontinent, there could be weak circulation, reducing its residence time over the region,” Tomar said.

There have been reports that Nepal, too, has seen a dry winter.

Delayed precipitation is compounded by reduced snow persistence, the time snow remains on the ground after snowfall. This means that when snow falls in February, while the minimum temperature remains low, the maximum temperature is relatively high, due to high diurnal temperature variation.

So, when snow falls, warmer temperatures reduce snow persistence, Tomar said.

“When it snows in December, moisture percolates and it gets retained for long periods. The melting process is also not rapid. This is beneficial for many rabi crops. Even if there is a delay in western disturbances after the first precipitation, an early snowfall/rainfall is beneficial,” Tomar said.

The situation is expected to change in the next few days, with the latest forecast suggesting light to moderate intensity rainfall over northwestern India during the January 18-20 period due to another approaching western disturbance. “Rainfall activity is likely to be below normal over the country, except the western Himalayan region and northwest India, where it is likely to be near normal to above normal,” the IMD said on Thursday.

Forest fires have also been raging in different parts of the Himalayas, and in particular, in parts of the Valley of Flowers range in the Nanda Devi National Park. This has been attributed to the lack of moisture in the forest floor, caused by decreased snowfall.

Since the beginning of the fire season on November 1, the Forest Survey of India has recorded more than 1,600 fire alerts in Uttarakhand, 600 in Himachal Pradesh, and around 300 in Jammu and Kashmir through the SNPP satellite.

With Himalayan glaciers already experiencing sustained mass loss, scientists warn that declining snow persistence and reduced winter precipitation could worsen the crisis.

Manish Mehta, a scientist at Wadia Institute of Himalayan Geology, said that glaciers could melt earlier than the season begins. “It could also result in the formation of proglacial and supraglacial lakes, increasing the risk of glacial lake outburst floods. Equilibrium line altitude, which marks the area or zone on a glacier where accumulation is balanced by ablation over one year, could shift upwards. As a result, the volume of discharge to rivers will also come down,” he said.