Why is the color of ice glaciers blue?

According to the RDPL: Because the orange (long wavelengths) part of white light is absorbed by ice and the blue (short wavelengths) light is transmitted and scattered. The longer the path light travels in ice, the bluer it appears

The purity and age of the ice also play an important factor in the color of ice in glaciers. As the ice ages it is compressed, melted and frozen again eliminating air bubbles that scatter the light rays and bounce them back out in the same color they came in (white). Once the ice becomes pure the light waves are much more likely to be absorbed promoting the deep blue color.