Jasper National Park consists of the top half of the spine of the Canadian Rockies. It is considerably more peaceful than its better known cousin of the south – Banff National Park. It is replete with stunning natural sites from glaciers and wildlife to deeply gorged canyons and lakes. You are much more likely to see wildlife in Jasper NAtional Park than you are in Banff National Park.
One of the lesser known but most interesting sites is so-called Medicine Lake. In summer, when most people visit – Jasper's summer population is apparently quadruple its winter population – the lake looks like any other. It is set among snow-capped mountains, has a range of wildlife around and is very striking but nevertheless, appears to be a typical glacial lake. Bears, elk and deer abound. Particularly busy are the frantic rabbit-like pika who use every waking minute to prepare food for the long northenr winter.
Wander through here in fall (autumn) and the lake will have disappeared. Remarkably, Medicine Lake is not a lake at all. Thought to be spiritual by the native Indians, the area has only a small drainage ability. With the intense water flows of late spring and early summer from the melting glaciers and mountain snow, the water pours into Medicine Lake much faster than it can drain, filling it until it appears to be a lake.
This is no different to turning a tap on fully into a basin, where the basin will keep filling as more water is going into the basin, than can escape through its drainage hole.
Eventually the water flow slows as the snows complete their melting and the cooler autumn weather starts the long winter cycle again. The water finally drains from Medicine Lake and it is no longer a lake.