NASA’s Landsat 8 satellite has captured incredible images of a new lake formed by a surging glacier in northern Pakistan. The new lake is being closely monitored by authorities due to potential for flooding.
While most Himalayan glaciers are retreating, about 200 in the Karakoram, a mountain range spanning the borders of Pakistan, India, and China, are actually doing the opposite, according to NASA. These glaciers cycle through periods when they abruptly flow several times faster than usual.
At peak speeds, surging glaciers can advance several meters per day—fast enough to block streams, bulldoze trees, crash into roads, and damage infrastructure. These surges typically last for a few months (and sometimes several years), and are then followed by a period of little or no movement that can last for a decade or longer.
The surging glacier in Pakistan sits near the 24,970-foot Mount Shishpar. In April 2018, the debris-covered glacier started to accelerate, with certain parts moving as fast as 43 to 59 feet per day. Since the surge started, the front of Shishpar Glacier has advanced by about 1 kilometer. As the ice pushed south past an adjacent valley, it blocked a meltwater stream flowing from the neighboring Muchuhar Glacier. By autumn 2018, the water had pooled up and formed a sizable lake.
Images acquired by the Operation Land Imager on Landsat 8 show the position of the glacier and lake on April 1, 2019 compared to April 5, 2018.
Scientists are now conducting frequent ground surveys near Shishpar and analyzing satellite imagery daily because the lake’s ice dams could collapse suddenly or lake water could spill over the dam and cause fast-moving, dangerous floods.
In the case of a severe flood, a nearby section of the Karakoram Highway, large numbers of homes in a nearby village, important irrigation channels, and two power plants could all be affected.
The glacier’s surge has already caused problems: One nearby power station went offline due to a lack of incoming water. A key pathway that miners and cattle once used to cross the glacier safely has also become impassable.
This is not the first time the Shishpar Glacier has surged. According to field research and analysis of satellite imagery, the Shishpar Glacier also surged in 1904-1905, 1972-1976, and 1993-2002.
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