Anyone who has visited Jasper National Park in the summer and driven up the Maligne Lake Road will surely remember Medicine Lake.
After all, the road twists along the shoreline of the seven-kilometre lake, treating tourists to jaw-dropping views across the lake to the mountains in the backdrop.
The lake is a must-stop location for hikes, picnics and selfies.
But by late fall, early winter, the lake magically disappears, leaving empty mud flats, high rocky banks and a meandering trickle of water. Tourists are left wondering where the famous lake they came to see is.
The Indigenous peoples of the area named Medicine Lake.
Year after year, the lake filled up in the summer and drained in the fall. With no apparent drainage system, the seasonal magic seemed like “big medicine,” hence the lake’s name.
It turns out the magic is in geology and not mystical spirits.
Underneath the lake lies an expansive underground cave system. In the spring and summer, glacial runoff from the surrounding mountains fills the cave system and the lake. At that time of year, the lake is like a bathtub with a fast tap and a slow drain.
About 24,000 litres of water drains from the lake and into the cave system every second! But runoff from the nearby mountains keeps the water level high all summer.
Once the runoff slows down in fall and winter, the lake empties, but it begins the cycle again with the lake filling in the spring.
The underground drain for the lake is huge, and it runs 17 kilometres downstream and resurfaces below Maligne Canyon. It’s the longest underground drainage system documented in Canada.
Interestingly, attempts in the 1950s were made to plug the drain in the lake by shoving mattresses and truckloads of newspapers into the cave entrances, but of course, these attempts were futile and ill-advised.
The exact timing of the lake draining is hard to predict. Some years, the draining takes weeks, while other times, it happens almost overnight.
Enough water remains in the lake basin over winter to support eastern brook trout that have been there since being first stocked in 1927.
The empty lake bed in winter makes a wide basin perfect for snowshoeing, cross-country skiing and exploring.
Whatever time of year you explore Medicine Lake, there are always surprises to be found, but you should no longer be surprised if the lake you came to see is no longer there!
