Lake Lucerne

Lake Lucerne was formed primarily during and shortly after the last ice age, through a combination of glacial erosion and river activity. During the last glacial period, large glaciers in the Alps flowed from the high mountains towards the foothills; in Central Switzerland, they carved out the valleys where Lake Lucerne now lies. These thick ice masses eroded the underlying bedrock, deepened existing river valleys, and formed characteristic, elongated, steep-sided basins similar to fjords.

Transition to a lake landscape
As the climate warmed and the glaciers retreated at the end of the Ice Age, the eroded basins were left behind as deep valleys. Meltwater from the disappearing glaciers and river runoff (primarily from the Reuss and smaller mountain streams) filled these basins, creating the lake we see today.

Role of rivers and current form
The Reuss River still flows through the lake, continually transporting sediment, but due to its great depth and complex morphology, the basin has not silted up and remains a deep mountain lake. The jagged, fjord-like shape of Lake Lucerne reflects the original glacial tongues that eroded the landscape in various directions, creating numerous inlets and tributaries (such as Lake Urnersee).

Dromos