Checking glacial lake outburst
In recent times, warming of the Himalayas is occurring faster than the global average of 0.74 C. This has caused the Himalayan glaciers to retreat faster than the world average.
No doubt, in the Himalayan region, some farmers have benefited from global warming due to an increase in growing season, permitting vegetable, wheat and maize farming at high altitude. However, the adverse impacts outweigh their benefits, which have not been realized by most persons of this region.
In Nepal, snow begins to melt in March and it continues up to August.
The velocity of glaciers varies from 50 meters per year in August to a few meters in winter, while advancing glaciers sweep away the debris to the terminal part and sometimes block the rivers flowing in different parts of the country.
While retreating, snow melting makes artificial lakes, especially in the neo-glaciation period.
It is well known to all that the Himalayan belt in Nepal abounds with glacial lakes. And each of the Himalayan range has at least five lakes in general. In recent times, new glacial lakes are found to be formed due to the retreat of the glaciers.
Some glacial lakes in this country are so swollen and unstable that they may explode at any time, bringing disasters and causing irreparable loss of many lives and wealth.
A research has shown that more than dozens of glacial lakes are potentially dangerous in Nepal. They are frequently overtopped by water, causing glacial lake outburst (GLO) downstream during the rainy season to the infrastructures such as bridges, powerhouses and roads.
In the past, some GLOs were counted by some concerned experts. According to them, they carry very high hazards.
Actually, frequent occurrence of GLOs not only damages the downstream infrastructure but also deposits heavy sediment load in the riverbed which ultimately will reduce reservoir capacity of dams to be constructed. In addition, GLOs will destroy the existing irrigation apart from wiping out vegetation.
In the meantime, Nepal lost a lot in 1985 when a GLO occurred in Khumbu in the Everest region, washing away a hydropower station, a trekking route to base camp and some bridges. Such GLO is possible in different parts of the country in the future at any time.
Therefore, it is imperative on the part of the authorities to install early warning systems near vulnerable glacial lakes to reduce the loss of the lives and the wealth of the concerned areas in the years to come.