Blindsee, Mountain lake in Biberwier, Austria

Blindsee is a mountain lake in Biberwier, Austria, sitting at roughly 1090 meters above sea level and covering around 26 hectares. The water reaches depths of about 25 meters and is known for its exceptional clarity.

Blindsee lies in a basin formed about 4,100 years ago by a huge rockslide that shaped the whole Fernpass valley floor; springs and surface water then filled the hollows between the slide mounds. In February 1984, after heavy snowfall, a slope on the lake's north side gave way; trees, branches and roots spread over the frozen surface, which soon broke, and the sunken trunks remain on the bottom.

The lake draws divers from across the region, who come specifically for its water clarity and the submerged tree trunks resting on the bottom. In summer, families and hikers gather along the shore to swim or simply sit by the water.

The road leading to the lake is only open to vehicles during set hours and generally requires a fee, so arriving early is a good idea. Weather at this elevation can change fast, so pack warm layers even if the morning looks sunny.

The name Blindsee means "blind lake" in German, which seems at odds with water clear enough to see 30 meters down. In summer, the water can warm up to around 24 degrees Celsius (75 Fahrenheit), which is unusually warm for a mountain lake at this elevation.