In 1975 , the lake was about 8 km ( 3.1 sq mi ) in area .
Now it reportedly stands at 18 km ( 6.9 sq mi ) at the edge of the glacier tongue .
In 1975 , the lake was about 8 km ( 3.1 sq mi ) in area and now it reportedly stands at 18 km ( 6.9 sq mi ) at the edge of the glacier tongue .