Glaciers are the master craftsmen of mountains. Down through the centuries their massive weight grinds down and rearranges the face of mountains. Glaciologist Jon Riedel takes a look at these rivers of ice, and their impact on the landscapes of North Cascades and Mount Rainier national parks, in this captivating video.
Deby Dixon, who works for the Park Service at North Cascades National Park, took this photo on July 29, 2012. Here's how she described the setting: