Why Is Glacier Ice Blue?

The glacier in these pictures is the Mendenhall Glacier in Juneau, Alaska.

Before I answer my own question I just want to point out how huge the glacier is.  We are at least a quarter mile away from the face in this picture.  The broken ice immediately in front of us creates the illusion that we can just reach out and touch the glacier.

To get an idea of the true size of everything in this picture look directly above the guy in the yellow coat to the very top of the blue section of ice.  Do you see the rock (just slightly to the left) sitting on the edge?  My brother and I were trying to guesstimate its size and we figure it’s at least the size of a car – and possibly as big as a bus.

I’m no glaciologist but I do know that when ice calves off of the glacier the newly exposed ice is very blue.  The section above just opened-up at the end of last summer.  As the ice is exposed to the air it starts to gets air bubbles forming near the surface.  The more this happens the whiter it becomes.

So, exactly why is the ice inside of a glacier blue?  For the same reason that pure water appears blue: because water absorbs the light waves that we see as the color red.   The ice inside a glacier is extremely dense so there are almost no air bubbles, meaning that glacier ice is a very good light filter.  Since the light waves that make the red-ish colors are absorbed by the glacier the light bouncing off of the glacier and into our eyes is blue.

I also think it’s interesting that the glacier looks slightly different depending on the weather – on overcast days the white really comes out.  One of my favorite times to go look at the glacier is during or just after the first real snowfall of the year.  The sky is cloudy so that makes (to my eyes) the colors ‘pop’ while the fresh snow hides the dirt that is on the glacier.  I only live two miles from the glacier so I get to see it under all different conditions.

This ice berg was very close to the visitors center so lots of people were walking out to it to take pictures.  So, why take a picture of other people taking pictures?  Because we were on ice skates.  Take a closer look at how rough the ice is around the ice berg – this was as close as we could get on skates.

The only way to get this close to the glacier during the summer is by water.  You can either rent kayaks and paddle yourself out or there is a guided canoe tour.  The canoe is modeled after Tlingit war canoes so it’s huge – not something you’d throw on top of your car to take to the lake.

If you want more information about either of these or if you have general questions about the Mendenhall Glacier just leave a comment.


5 thoughts on “Why Is Glacier Ice Blue?

  1. Pingback: Exciting Eyjafjallajökull in a Super-Jeep! « Fika After Fifty

  2. Pingback: Icebergs « The Other Alaska

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