Hydrology of the Nahanni karst, northern Canada, and the importance of extreme summer storms

Discovered in August 1971, the Nahanni karst is the most complex high-latitude karst known. Mean annual temperature is −4.5°C and precipitation 566 mm. The most spectacular landforms occur on a structural col (the “north karst”) connecting south Nahanni and Ram Plateau. Between July 19 and 31, 1972, an extreme summer storm deposited 224 mm of rain on the area. First, Second and Third Poljes in the north karst flooded; maximum water depths were …