Altausseer See is a 2 km long glacier-carved lake south of the Loser plateau. Its north shore lies on a significant fault which marks the SE boundary of the block of limestone of which Loser is made. A number of small resurgences feed the lake, but in dry weather none of those above the surface carry anything other than very local drainage.
Within the lake are a number of underwater resurgences. These appear to lie on the fault itself, and explain why the deepest points of certain caves coincide with the level of Altausseer See at 712m above sea level.
In much wetter weather, water emerges from flood risings on the north shore or much higher on the hillside. The closest to the lake, Wasserlöcher, is associated with a significant cave, Liägerhöhle. Another major stream course enters the lake further west, near some boat houses and places of refreshment at the end of the motorable road. This is normally dry, but apparently carries huge volumes of flood water from risings at about 1080m in Kiler Lahn, a steep gully. We know of no documented caves in this gully, which is in a rather inaccessible position.
To the northeast of the lake, ("behind" it, as seen from the village of Altaussee) a glacier-carved valley rises to the pass of Hochklapf Sattel. A steep path can be followed up through woodland to join the Stögerweg path from the Stellerweghöhle area, which continues NE to Wildensee. There are a few caves west of this path, below the cliffs of Weiße Wand.