The colors of glaciers never cease to amaze me. Yesterday I crawled into this strange muddy tunnel and saw the ice turn purple. I can't seem to find why that would happen, but I wonder if it has to do with light coming into the tunnel mixing with the deep blue coming in through the walls. @outdoor_okay I seem to remember you talking about some purple ice, any ideas? Or @jason_gulley_science ?
Note the light coming in below from a moulin intersecting the tunnel.