Feast your eyes on Alaska's Susitna Glacier. Why does it look reddish? According to NASA, glaciers pick up bits of dirt and dust from the ground as they travel with tributaries toward larger rivers.
Here's more on what the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) captured as it passed over the Susitna Glacier:
This satellite image combines infrared, red and green wavelengths to form a false-color image. Vegetation is red and the glacier's surface is marbled with dirt-free blue ice and dirt-coated brown ice. Infusions of relatively clean ice push in from tributaries in the north. The glacier surface appears especially complex near the center of the image, where a tributary has pushed the ice in the main glacier slightly southward.