Travel the Alaska Marine Highway System from Valdez to Whittier, and you will experience the Columbia Glacier enroute. The vessel will slow down so you can get a long look at the largest tidewater glacier in Southcentral Alaska. The US Forest Service on board provides a narration on the sight. Columbia Glacier's face rises 250 feet from the sea and spans three miles across the bay. This river of ice flows to the sea from the Chugach Mountains and blankets an area over 400 square miles.
Why does glacier ice look blue? It is often a deep blue color because as sunlight passes through the ice, it’s broken up into its many inherent colors and energy wavelengths. Red and yellow have very little energy and the thick ice soaks them up readily. The blue light has enough extra energy to escape from the ice crystals without being absorbed.
If there are a lot of air bubbles inside the ice, the sunlight isn’t soaked up, but reflected back to our eyes. If the light can pass through the ice without all the rainbow colors being scattered, the ice will look white. Glaciers often pick up soil, rocks, snow and dirt that mix with the ice, which can then take on a dirty gray color.
