The Medvezhiy glacier, located in the Pamir Mountains, has moved almost 3,300 feet since June 3, NewScientist.com reported Thursday.
Known for periodic bursts of speed, the glacier has reached the point where it is now blocking the Abdukagor River, prompting worries of flooding as a glacial lake 650 feet deep and 1,150 feet wide has formed behind it.
In its last major movements, in 1962 and 1973, the glacier advanced by as much 1.25 miles, later releasing 700 million cubic feet of water once the Abdukafor breached the glacier's ice dams.