Between Vadret da Morteratsch and Pers, 2480 m.a.s.l.: Where Vadret da Morteratsch (coming from the left) and Vadret Pers (from the right) join, two lateral moraines [1] form a medial moraine [2]. Towards the end of the Little Ice Age, around 1850, both glaciers were considerably thicker than today, as shown by tall lateral moraines [3] which dam a small glacial lake [4].
From the small mountain glacier [5] a meltwater stream flows into the lake. In the 19th century the small glacier was much larger and reached all the way down to Vadret da Morteratsch. The lake appeared only after its retreat.
