Running Eagle Falls, The Double Waterfall
Running Eagle Falls, or Pitamakan, is just one of over 200 waterfalls in Glacier National Park, Montana but it is unique in that it can be two waterfalls in one. For this reason it has also been called the Trick Falls. Erosion has created a natural bridge that spans the width of the falls. The lower falls flow year round and are about 6 m tall. During the spring, water flow from snowmelt is so high (average annual snowfall in Glacier is around 80 cm) that water will flow over the natural bridge, which is 12 m high. As seen below, there are many phases that the falls go through. During peak snowmelt times, the two falls are indistinguishable from each other as the upper falls completely overtake the lower falls (Left). As spring turns into summer, snowmelt flows subside and the upper falls become more a trickle (Top right). The last photograph was taken in late August 2014, when the upper falls have completely disappeared. This cycle has repeated itself for thousands of years, creating the truly unique waterfall seen below.
-JRA
Sources: http://www.nps.gov/features/glac/maps/runningea.htm http://www.hikinginglacier.com/running-eagle-falls.htm
Image Credits: National Park Service/Tim Rains http://bit.ly/1RObe4O National Park Service/Jacob W. Frank http://bit.ly/1RvpLQj Personal Collection of JRA