Due to rise in mercury level, glaciers around the world are at risk of melting but Shimshal valley in Upper Hunza faces natural disasters like floods and glaciers lake outburst as the glaciers in the valley are surging.
Under the phenomenon of “Karakoram Anomaly” more than 120 glaciers in Pakistan are stable or even growing, experts say.
In 2017, Britian’s Newcastle University attributed the anomaly to a summer “vortex” of cold air over the Karakoram mountain range which causing the glaciers in the region to grow in spite of global average increase in temperature.
Surging Khurdopin glacier in Shimsal valley is one of the great concern as it is in surge phase since May 2017. The surging glacier blocked the flow of Shimshal River, a tributary of Hunza River last year and resulted in a large lake. The fear among the residents and the officials is growing that the lake which is almost frozen can cause outburst flood in coming summer days.
Khurdopin glacier is known for causing periodic glacial outburst floods that have led to massive destruction not only in Shimshal valley but even to downstream. In August 2017, glacier affiliated flash floods caused a havoc in the valley by destroying bridges and road network.
When 47 km long Khurdopin glacier collides with the side wall of the rocky valley, it blocks the river, and a temporary lake forms behind it as the water piles up. The lake expands for several months and then can burst through the blockage as the glacier retreats again. By January of this year, the lake was already about 1.5km (1 mile) in length.
Scientists studying the Khurdopin glacier using satellite imagery have confirmed that it is moving at a rapid pace. A study by Utrecht University reported that during a few weeks in 2017 the glacier’s velocity peaked at the equivalent of 5 km a year, among the fastest rates reported globally.
According to Dr. Ghulam Rasul, DG Pakistan Meteorological Department, who viewed the glacial lake from a helicopter last December, estimates that it is at 70 percent of its capacity, with no inflows at the moment, but that it will fill up further as ice begins to melt around the end of March. “In mid-March, inflows will start increasing. In April it will reach a high-risk position. In my opinion the lake will flow over the ice or make a channel for itself through the ice. I don’t expect a sudden outburst,” Rasul said.
In the meantime, however, residents of the Shimshal valley are keeping a watchful eye on their glacier – and the frozen lake behind it.
Satellite images by NASA