Stappitzer See, Natural lake in Mallnitz, Austria.

The Stappitzer See is a mountain lake in the Hohe Tauern National Park near Mallnitz that covers about 8 hectares. The water body reaches a maximum depth of roughly 6 meters and sits at an elevation of 1273 meters.

The lake formed during the last glacial period when a landslide blocked the Mallnitz valley, creating a natural water barrier. This geological event shaped the basin thousands of years ago.

The lake is a stopover for birds crossing the Alps, among them the black-throated loon (Gavia arctica) and the western yellow wagtail (Motacilla flava). Its little grebe (Tachybotus ruficollis) breeding sites rank among the highest in Austria. Alpine swifts and Eurasian crag martins hunt insects over the water and the surrounding silted shore.

The lake lies at 1273 m in the Seebachtal, in the peripheral zone of the Hohe Tauern National Park above Mallnitz. The site is a protected nature monument and European bird sanctuary, so visitors should stay on paths and keep their distance from the shore and the reed belt. Mountain weather changes quickly; sturdy footwear and rain gear are useful.

The basin holds roughly 130000 cubic meters of water and maintains an average depth of about 3.6 meters. These measurements show how the water body stays relatively stable despite its mountain location.