On our return from Maligne Lake to Jasper, we stopped by at the Medicine Lake. A geological wonder, Medicine Lake is perhaps best described as a sinking lake. In summer, the lake fills more quickly than it can drain away. The glacier melt waters flood the lake in summer, sometimes overflowing it and the body of water appears deep and expansive. In fall and winter the lake disappears, becoming a mudflat with scattered pools of water connected by a stream.
Where then does the water go?
‘Out through the bottom’ like a bathtub without a plug. The Maligne River pours into the lake from the South and the lake waters drain out through sinkholes in the bottom. The water then streams through a cave system formed in the slightly soluble limestone rock, surfacing again in the area of Maligne Canyon 16 km downstream. This is one of the largest known sinking lakes in the Western Hemisphere and may be the largest inaccessible cave system anywhere in the world.
Summer melt water coming into the lake exceeds the amount the sinkholes can drain. Decreased melt water in the late summer and fall means that the lake’s sinkholes can drain the lake faster than what the Maligne River can fill. This creates the disappearing lake phenomena.
This natural phenomenon bewildered Aboriginals and other early visitors. They found no apparent water outlet, but the lake sank in winters. Many in the early days attributed it to some spirits or demons sucking away the water in winter. Aboriginal people called the lake Medicine Lake because of its seemingly magical powers and the United Nations declared the Rocky Mountain Parks a World Heritage Site partly because of this unique drainage system.
Wolves in the region have figured out how to make it work for them. They have been known to chase caribou into the muck so they get slowed down or stuck.
Prior to the construction of the road around Medicine Lake, the irregular water levels made it difficult to get visitors to Maligne Lake. Shallow bottomed boats were employed, but they ran aground on sandbars or capsized in strong winds prevalent in the area. In an attempt to establish higher water levels, in 1930’s, the park superintendent ordered that old magazines and mattresses be thrown into the lake to plug the drainage holes and allow the lake to fill. The scheme failed to work, and no one ever tried such tricks to fool mother nature ever after.
The park officials even suggested building a dam to close the sinkholes to stem the outflow of water. It was also given up as they realised that the sinkholes were immense and needed many truckloads of soil to fill them up. It was in 1956 after Jean Corbel, a French scientist who concluded that a sinking river system had been created much before the last ice age.
These cave systems till date remain the largest inaccessible cave system in the world. In case someone attempts to go down through them, they will surely find the old magazines to read when bored.
After leaving Medicine Lake, we drove down to Maligne Canyon. The Jasper Parks have created a trail for the tourists to hike and follow the canyon as it flows down on its way to the Athabasca River which further drains into the Arctic Ocean.
The Maligne River after draining into the Medicine Lake seem to disappear and then re-emerge 16 km downstream near Maligne Canyon. Some geologists speculate that parts of the canyon were originally deep caves that have since been uncovered by glacial scraping and water erosion. This scraping of the caves lead to the canyons being narrow at the top and wider down below.
Before the last ice age ended 14,000 years ago, the Maligne Valley was buried under a glacier about a kilometre thick. Glaciers moved and the heavy ice and rock at the bottom of the glacier eroded the valley floor until it broke into the cave, later tearing the roof away. The glacial ice invaded the passage, grinding much of it away until the climate warmed and the remaining ice melted away. What was left –the geologists theorise was the Maligne Canyon.
Another interesting thing about the Maligne Canyon is that more water appears to flow out of the gorge than flows in at the ground’s surface. Most of the water in the canyon area flows underground through a cave system, 30 km long, that carries it from Medicine Lake 14 km away to Maligne Canyon’s many springs.
The underground system is extensive and during the 1970s researchers used a biodegradable dye to determine the underground river’s extent. The dye showed up in many of the lakes and rivers in the area and it became clear that the underground system was one of the most extensive in the world.
Walking on the trails along the canyon was awe-inspiring. The gorges were breathtaking, with its rushing waters and steep walls. In some places the walls narrowed, forcing the large volume of water through a series of rapids. The areas of the gorges are fenced off, as a fall here could prove fatal.
These geological wonders are one of its kind in the world and are always worth a visit.