on Mt. McKinley It was so fascinating to fly over the glaciers on the mountain! Glaciers are "rivers" of ice that flow very slowly. The long black line in the middle of the glacier is a medial moraine, made up of ground up rock where 2 glaciers meet as they flow down from the mountains.
The blue-tinted cracks are deep cravasses in the glacier. Cravasses form in quicker-moving areas of a glacier. Glaciers form when snow builds up faster than it can melt. Over time the snow compresses forcing the air out, creating very clear ice. This ice absorbs all the colors of the spectrum except blue which is reflected giving the glacier its beautiful blue hue.
