SHIMLA: The scientists say that the analysis of snow in 2022-23 showed a decline in snow cover area for the entire Himachal Pradesh Himalaya, with Chenab, Beas, Ravi, and Satluj basins experiencing declines ranging from 0.39% to 22.42% compared to the previous year.
They share the findings here today at a progrmme held by State Centre on Climate Change, operated by the HP Council for Science Technology & Environment (HIMCOSTE) under the Government of Himachal Pradesh.
They say HIMCOSTE has been conducting studies to understand the impact of climate change on various aspects of the state. Himachal Pradesh receives winter precipitation in the form of snow, particularly in higher altitudes, where about one-third of the state's total area remains under thick snow cover.
Based on recent studies, the winter precipitation in Himachal Pradesh was analyzed for different basins- Chandra, Bhaga, Miyar, Beas, Parvati, Jiwa, Pin, Spiti, and Baspa.
HIMCOSTE uses AWIFS satellite data with a spatial resolution of 56 meters from October to April.
The analysis of the 2022-23 snowfall revealed the following trends:
It found that in October and November, early snowfall resulted in positive trends in the Chenab and Beas basins. But the Ravi and Satluj basins experienced a decrease in snow cover area.
During the peak winter months (December to February), all four basins showed negative trends compared to the previous winter period. The Ravi and Satluj basins were the most affected, while Chenab and Beas had relatively better results.
In comparison to the previous year, the Chenab basin exhibited a decline of about 36% in October, while Ravi and Satluj experienced larger declines.
However, Beas showed a slight increase in snow cover area.
Similar patterns were observed in November, with Chenab and Beas showing enhancements and Ravi and Satluj experiencing declines.
In December, Satluj basin saw the largest decline (56%), while Chenab had the smallest decline (10%).
The declining trend continued in January and February for all basins, with varying degrees of decline.
In March, all basins experienced a decline in snow cover area.
In April, at the start of the summer ablation period, there was an enhancement in snow cover area in all basins.
Based on these findings, the Chief Secretary of Himachal Pradesh Prabodh Saxena expressed concern about the rising temperatures in the higher Himalayan region, which are affecting the region's glaciers and snow reserves.
The change in snowfall patterns during winters is also impacting river discharge during the peak summer season. He emphasized the need for concrete steps, such as the introduction of electric vehicles and the adoption of renewable energy, to reduce greenhouse gas emissions and mitigate the rise in temperatures.
Glaciologists say that the seasonal snow cover plays a crucial role in the discharge of major rivers such as Chenab, Beas, Parvati, Baspa, Spiti, Ravi, Satluj, and their tributaries.
They depend on the snow for a consistent water supply and in turn for hydropower projects on the river basins in the region.
Additionally, the snow cover helps regulate the accumulation and melting patterns of glaciers in the state.
To determine the extent of snow cover during the winter season, the Centre has been using satellite data of various resolutions to map the geographical area covered under snow.
“This mapping is essential to understand the contribution of snow in different catchments and sustain the hydrology of river basins”, they say.
