We normally see that brilliant blue in an open crevasse.
But, why is it blue?
Red (long wavelengths) part of white light is absorbed by ice.
Blue (short wavelengths) light is transmitted and spreaded. The longer the path light travels in ice, the more blue it appears.
In ice, the absorption of light at the red end of the spectrum is six times bigger than at the blue end. So, the deeper light energy travels, the more photons ("a quantum of electromagnetic radiation, usually considered as an elementary particle that is its own antiparticle and that has zero rest mass and charge and a spin of one" dictionary.com) from the red end of the spectrum it loses along the way. Two meters into the glacier, most of the reds are dead. A lack of reflected red wavelengths produces the color blue in the human eye.
The light has to move deep into the ice and the colours of the spectrum are absorbed, expect the blue.
Ice appears white, at the top, because small pockets of air reflect and spread visible light.
Ice only appears blue when bubbles do not interfere with the passage of light.
Others believe that the reason why the ice is blue is the same why the water appears blue.