Himachal snow cover shrinks down further
On the brink of worst ever water crisis, Himachal Pradesh is yet to recover from persistent sweltering heatwave, abrupt rise in Mercury and prolonged dry season, moreover scientists came with another bad revelations that Himachal Snow caver is vanishing quickly as area under glaciers are furthers receded. It is worthwhile to mention that ups and downs are there due to erratic weather pattern round the snowfall season. Study suggested from its data that in winter or snow seasons during 2021-22 (Oct – April ) it witnessed increased in early half (Oct. & Nov.), which further reduced in peak winter months and further increased during late winter period (i.e. Feb & March ). It slightly improved in the last winter snowfall compared to pervious 2020 -21 winter period. However due to the rise in temperature from March & April in 2022 , the snow cover area melted fast in comparison to 2021. The Report says that comparative temperature and long heatwave attributed to fast thawing of Glaciers in the states. Snow cover recedes(thawed) about 15 per cent more this year that of last year. In all the five rivers’ basins which originates from long ranges of glaciers were melting at accelerated rate in all the basins , thereby leading to reduction of snow cover area in each basin which ranges between 19-25 pc in 2021 22 in March & April in comparison to 4-10 pc in 2020-21 during the same period. The abrupt rise in Temperature in different basins reported in between 2021 & 2022 in the state. During the month of March in Chenab basin. The Maximum temperature increased by 1.3 degree Celsius . In April soar high up to 8.3 degrees and three degrees in May. In the Ravi basin the temperature increased was 2.3 in March , 6.1 in April and 3.5 in May. in Chamba and at Dalhousie the increase was 2.1 , 7.6 & 5 degree in March to May. In Beas basin it increase, 3 in March, 7.3 C in April and 4 in May. At Bhuntar and at Manali the increase was of the order of 3.7 , 6.2 and 2.6 in March , April and May respectively. Likewise the temperature increase in Satluj basin was of the order of 2.8 in March and 8.2 in April and 2.9 degrees in May between 2021 & 2022. Due to this abrupt rise in temperature in 2022 between March and April Basin wise percentage area uner snow which would meet out the water requirement at the end of April was 66 p c ( Chenab ), 36 p c ( Beas ), 21 pc ( Ravi ) and 33 pc( Satluj ) during the ablation season (May on ward).Based on the analysis carried out , it is concluded that in the 2021 -22 winter period ( Oct – April ) an overall increase in the spatial distribution of the snow cover area of the order of 19.47 per cent was observed in comparison to the total area under snow in 2020-21 winter period, which was about 18 pc less in comparison to 2019-20. Further during 2021-22 , there was early snow fall in the month of October & November , there by leading to have positive trends in all basins . During peak winter months ( December – February ) , two basins i.e. Chenab & Ravi have negative trends like that of the last winter , whereas the Beas and Satluj basins were characterized by positive trends and this variation may be due to the fact that the Chenab and Ravi which are adjacent basins along the Pir Panjal Range must have controlled the western disturbance in this region. whereas the Beas and Satlu ) which are on the south and south eastern side , reflecting positive trend may have the intersection of the another disturbance arising out from the southern side . About 1/3rd of the total geographical area of the State remains under thick snow cover during the winter season. Most of the major rivers like Chenab , Beas , Parvati , Baspa , Spiti , Ravi Satluj and its perennial tributaries originating from the Himalayas depend upon the seasonal snow cover besides the glacier input for then discharge dependability besides this , the snow cover also helps in controlling the accumulation and ablation patterns of the glaciated regions in the State. Snow Study is conducted every year and its report announced in second weak of June at the onset of monsoon or pre monsoon. State receives winter precipitation in the form of snow at the higher altitudes therefore report is complied by the Himachal Pradesh Council of Science, Technology and Environment said that studies are being carried out by the Center for mapping of seasonal snow cover in terms of its spatial distribution covers the different river basins in Himachal Pradesh. Every winter season during the month of October to April center for mapping collect important input with help of manual, satellite and graphic collection of data which is later compiled into reports in order to understand the contribution of snow in different catchments to sustain the hydrology of the river basins. Considering the importance of seasonal snow cover as a major input in controlling the hydrology of the river basins , Director ( Env ) -cum- Member Secretary ( HIMCOSTE ) Mr.Lalit Jain (IAS) apprised that although we have the information about the total snow fall that takes place during winter season from the various observatories operating through out the State as a point information , but their spatial extent cannot be ascertained that contributes in enhancing the discharge dependability of the river systems in the Himalayas. He said that studies are robust and free of back lashes using satellite data of different resolutions , it has now become possible to map the geographical extent of the area covered under snow during winter season . He further said that the studies which are being carried out by the Center for mapping of seasonal snow cover in terms of its spatial distribution covers the different river basins in Himachal Pradesh during the winter season from October to April and is an important input in order to understand the contribution of snow in different catchments to sustain the hydrology of the river basins.
