Himachal skating on thin ice as winter snow cover drops 10%
Himachal’s centre for climate change mapped the reduced snow cover’s impact on volatile ecology and river basins
The mountains across the state witnessed a 10% decline in snow cover between 2022-23 and previous year’s winter season, a study conducted by the Himachal Pradesh Council for Science, Technology and Environment’s (HIMCOSTE) State Centre on Climate Change showed.
Himachal receives winter precipitation in the form of snow across the higher altitudes, with about one-third of the total geographical area of the state remaining blanketed under a thick cover of snow during the winter season.
The same is ecologically significant given that major rivers like the Chenab, Beas, Parvati, Baspa, Spiti, Ravi, Satluj and its perennial tributaries originating from the Himalayas depend upon the seasonal snowfall for their discharge dependability. Besides, the snow cover also helps control the accumulation and ablation patterns of the state’s glacial regions.
Given the seasonal snowfall’s impact on hydrology, Environment, Science and Technology-cum-HIMCOSTE member secretary director DC Rana said the study to map seasonal snow cover between October and April and its contribution to different catchments that helps sustain different river basins was important.
Rivers’ flow take a hit
Considering the present trend of winter snowfall in Himachal, the winter precipitation was mapped across basins of Chandra, Bhaga, Miyar, Beas, Parvati, Jiwa, Pin, Spiti and Baspa using Advanced Wide Field Sensor (AWIFS) satellite data having a spatial resolution of 56 m.
During 2022-23, snowfall was estimated and analysed with reference to the average value of the total area under snow in each month from October to April, Rana said, adding, “Based on the analysis, there was early snowfall in the month of October and November, thereby leading to positive trends in Chenab and Beas basins, whereas the Ravi and Satluj had the negative trend.”
It is found that the Chenab basin recorded a near-36% decline from 2021-22, Ravi 54% and Satluj around 27% during the month of October. Beas, meanwhile, showed a slight 3% enhancement in its area in 2022-23.
Likewise, in November, Chenab and Beas basins showed 5% and 21% enhancement in its area respectively, while Ravi and Satluj were down 3% and 22% respectively.
During peak winter, between December and February, all four basins i.e. Chenab, Beas, Ravi and Satluj had negative trends in comparison to last winter. The worst affected basins were Ravi and Satluj, while Chenab and Beas fared relatively better.
The highest 56% decline was witnessed at the Satluj basin in December, 38% whereas in February. Beas fared the worst in February, recording a 32% decline.
The declining trend continued in March with around 2% drop in Chenab, 5% in Beas, 7% in Ravi and about 4% in Sutlej.
At the start of the summer ablation period in April, the snow cover increased across the four basins. Chenab’s basin was enhanced by 22%, Beas by 39%, Ravi by 54% and Satluj by 29%.
Glaciers losing mass: Study
State centre chief secretary Prabodh Saxena said the study showed the temperature on the higher Himalayan region were comparatively higher than the low-lying areas, which was affecting Himalayan reserves — evidenced by the fact that most of the glaciers are losing mass.
Besides, a significant shift was observed in the snowfall patterns during winters, something that affected the river discharge during peak summers.
Saxena also noted that the impact of rising temperature was also witnessed in capital Shimla, which did not receive any snowfall this winter. That, he said, showed a major change in the weather patterns, adding, “If this continues, we will have to start thinking about a possible shortage of water in the coming years.”
He went on to express hope that concrete steps such as introduction of e-vehicles, shifting to renewable energy, are taken.
- Himachal Pradesh