The mystery of Medicine Lake...

In summer, Medicine looks like any other lake in Jasper National Park. But by october the lake vanishes, replaced until spring by a shallow stream winding sluggishly across mudflats to a few small pools. The water's depth varies as much as 20 m through the year. Much of the time, the lake has no visible outlet.
Indians believed the disappearance of the lake was by "big medicine" or magic, and they feared it...