Medicine Lake in Jasper National Park is a geologic anomaly. Melt glacial water flows from Malign Lake via Malign River into Medicine Lake. However, there is no visible channel draining the lake. Instead, the water drains through sinkholes in the bottom of Medicine Lake, surfacing again 16km downstream in Malign Canyon!! This is one of the largest known sinking rivers in the Western Hemisphere and may be the largest inaccessible underground water system anywhere in the world!!
During summer, melt glacial water coming into the lake exceeds the capacity of the sinkholes to drain it, producing this lovely “Medicine Lake”. In other seasons, the lake’s sinkholes drain the lake faster than Maligne River can fill it, leading to a mud flat with scattered pools of water. This creates the disappearing lake phenomenon. Native peoples called the lake Medicine because of its seemingly magical powers, and the United Nations created the Rocky Mountain Parks World Heritage Site partly because of this unique drainage system.
Medicine Lake is a fly fisherman’s paradise for rainbow trout and brook trout.
Exact location of this lake is indicated by Green Arrow on the map below.
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