In flows into Prince William Sound, the columbia Glacier is one of the largest tidewater glaciers. This is an aerial view showing how irregular the face of the glacier is. Notice the calved icebergs and the blue color of the glacier. It is blue because glacial ice is not formed by freezing water but by compacting snow. The pressure drives out the air and makes a denser ice. The blue light from the sun’s solar spectrum reflects off this ice.