As glaciers melt they form rivers of glacial water. Sometimes these streams bump into the lateral boundaries of larger neighboring glaciers. The larger glacier acts as a dam, and a temporary lake begins to form. Glacial melt-off continues to pour into the lake for many months and the lake level begins creeping up the sides of the surrounding valley. As the water level rises the glacier dam continues to melt, calving huge chunks of ice into the lake. Now the lake is brimming with massive icebergs. Eventually the lateral boundary, or edge, of the large glacier becomes buoyant with the deepening water. As the edge of the glacier begins lifting, a chasm is opened and the lake begins draining. Slowly at first and then with an increased intensity as the water carves a path. In a very short time (1-3 days) millions upon millions of gallons of water rush beneath the ice for several miles eventually pouring out at the toe of the glacier. This is known as Glacial Lake Outburst Flooding (GLOF). I promised a blog entry on GLOF on Dec 14th.
The video shows what this lake looks like before, and after the flood. We fly over this lake on a regular basis, so we see the first signs of drainage and alert the Alaska River Forecast Center. The lake is most spectacular within the first 48 hours of drainage because the icebergs are still saturated with water thus showing a deeper blue. As time passes the chunks of ice will become white in color as the water drains out of them. These icebergs are monstrosities teetering on uneven footing. While they lay like beached whales on the gravel bars huge chunks of ice continue to break off. I have had the privilege of walking among these giants and it is an awesome experience. With my wife’s company, BackPackAK.com, this is one or our favorite trips. We land out on the glacier and then hike around/through the lake, and up and over a beautiful mt. pass with waterfalls and mountain lakes. This is an excellent hike, unique beyond imagination.
Turn the volume up because these are some good tunes.