Snow cover needs more studies

Cryosphere: Researchers are calling for more studies on snow cover in Bhutan given the declining snowfall the country has been experiencing over the last decade.

According to International Center for Integrated Mountain Development (ICIMOD),  remote sensing specialist, Deo Raj Gurung, the declining trend in snowfall is worrying because snowmelt acts as a buffer for the river systems.

This year, Thimphu declared no snowfall holiday, while it snowed for only half a night in Bumthang.

“To know what’ll happen to the river system, a good understanding of snow cover is crucial for research and adaptation,” Deo Raj Gurung said.

Although they seem similar, snow cover and glacier are different.

Glacier is an accumulation of compact snow for years, while snow is a source of glaciers.

Deo Raj Gurung said studies on snow cover are hardly conducted in Bhutan, even though snow is understood as a major contributor to the major river systems.

“There is comparatively more information on glaciers in Bhutan than snow cover,” Ugyen Wangchuck Institute for Conservation and Environment’s (UWICE) director, Nawang Norbu, said.

Yet, he said, more people are continuing to study glaciers.  For instance, even in the recent international symposium of glaciers, only one presentation of the nine made was on snow cover.

Thimphu-based environment and civil engineer, Chhimi Dorji, also said that, although initiatives were slowly taken up to study snow cover, little was known historically of snow in Bhutan.

“For instance, the only information on history of snow in Bhutan was from Kuensel, where it ran stories on the public holiday during the first snow every year,” Chhimi Dorji said.

Department of hydromet services’ officiating chief of snow and glacier division, Tshering Tashi, also said that snow cover studies still received little attention from policy makers, despite being scientifically as important as rainfall.

According to Deo Raj Gurung, understanding the three facets of cryosphere – permafrost, snow cover and glacier – is important to quantify water availability.

“While permafrost remains unexplored at all, even snow cover in Bhutan is hardly studied,” he said.

Snow cover plays a vital role in the river hydrology during winters when the volume of rivers shrinks to just 10 percent from 100 percent in monsoons.

“Snow cover is crucial to maintain that 10 percent of river water in winters,” Deo Raj Gurung said.

He said that, without snow cover, the rivers could run dry, as there was neither rainfall nor water from the glacier melt in winters without snow in the upstream.

“As a result, Bhutan’s hydropower projects could suffer with rivers drying up,” Deo Raj Gurung said.

Also, fresh snow has a higher capacity to reflect back the sunrays to insulate the earth from the sun’s heat, he said.  It is said that fresh snow has an ability to reflect back 70-80 percent of the rays.

Nawang Norbu said global climate change couldn’t be controlled. “Which is why it’s important study snow cover because of Bhutan’s dependency on agriculture and hydropower,” he said.

Snow cover study is also confronted with numerous resource constraints such as manpower, expertise in metrology, snow monitoring station and field studies.

“The division is also suffering from lack of remote sensing with higher capacity for mapping snow cover besides software to record data at desk,” Tshering Tashi said.

By Tempa Wangdi, Bumthang

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