A tarn is a mountain lake, pond or pool, formed in a cirque excavated by a glacier. A moraine may form a natural dam below a tarn.
Verdi Lake in the Ruby Mountains of Nevada
Veľké Hincovo, Tatra Mts, the largest and deepest tarn in Slovakia
Lakes of the Clouds, below Mount Washington in the White Mountains
Banderishki Chukar seen from the Banderishki Lakes (tarns), Pirin Mountain, Bulgaria
A cirque is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie and cwm. A cirque may also be a similarly shaped landform arising from fluvial erosion.
Two cirques with semi-permanent snowpatches near Abisko National Park, Sweden
Upper Thornton Lake Cirque in North Cascades National Park, U.S.
Maritsa cirque in Rila Mountain, Bulgaria
The Lower Curtis Glacier in North Cascades National Park is a well-developed cirque glacier; if the glacier continues to retreat and melt away, a lake may form in the basin