Performance of Snow Fence at Banihal Top in Himalayan Region

A continuous snow fence of 50% porosity, 130 m in length, and 4.0 m height was installed to overcome the snowdrift problems at Banihal Top (Jammu and Kashmir, India) in the Himalayan region. The avalanche sites, which affect the north and south Portals of the Jawahar Tunnel, have catchment areas near Banihal Top. The width of mountainous ridge at this site is about 60 m except within a central depression area where the width is about 200–250 m. Snow mass is eroded from the southern windward slope and deposited on the northern leeward slope toward the Kashmir valley during the winter. The rates of erosion and deposition of snow are controlled by snow characteristics, the snow surface roughness, terrain features, and the snow fence configuration. The snow at Banihal Top is wet in nature and snow deposition due to snow drifting is found to be about $105{\mathrm{m}}^3$ per running meter of snow fence having a height of 4.0 m. The storage capacity of this snow fence is higher than that of previously installed snow fences of 3.0 and 3.5 m heights. The extension of deposited snow on the leeward side of the snow fence is found to be 15–17 times the snow fence height; this is comparatively smaller than the extension of drifted snow mass reported in Western countries. It is observed that the nose of the drifted snow profile is shifted toward the snow fence with a reduction of the snow fence porosity due to snow riming. Change in porosity due to snow riming of the fence reduces its capacity but it serves to accumulate more snow if the riming happened after the aerodynamic equilibrium state is reached. The snow fence has reduced the snow mass accumulation in the formation zone of the avalanche site. It has also helped to prevent blockage of the national highway NH-1 A and the North Portal of the Jawahar Tunnel in Jammu and Kashmir, India.