Why is glacier ice blue?

Glacier ice appears blue to us for the same reason that the ocean appears to be blue. The wavelengths of the visible spectrum of light that are reds and greens (500-740 nm) are preferentially absorbed by water and ice while the shorter wavelengths of the visible spectrum (the blues and purples, 380-500 nm) are typically reflected and are visible to the human eye ¹. The longer the light travels into the object, the more blue it will appear, which also why we do not perceive this effect when we put an ice cube in our soda.

Cited information:

¹ Benn, D. I., Evans, D. J. A. (2010) Glaciers and Glaciation. Hodder Education (https://books.google.cl/books/about/Glaciers_and_Glaciation.html?id=c0xNAQAAIAAJ&redir_esc=y)

Written by Thomas Shaw.
Edited by Equipo Glaciar.