This is Hidden Brain, I'm Shankar Vidadhu.

Last year, my family and I took a vacation to Alaska.

This was a much needed, long planned break.

The best part?

I got to walk on the top of a glacier.

The pale blue ice was translucent.

Sharp ridges opened up into crevices dozens of feet deep.

Every geological feature, every hill, every valley,

was sculpted in ice.

It was a sunny day and I spotted a small stream of melted water.

I got on the ground and drank some.

I wondered how long this water had remained frozen.

The little stream is not the only ice that's melting in Alaska.

The Mendenhall Glacier, one of the chief tourist attractions in Juneau,

has retreated over one and a half miles in the last half century.

Today you can only see a small sliver of the glacier's tongue from a lookout.

I caught up with John Neary, a forest service official who tries to explain to visitors

the scale of the changes that they're witnessing.

I would say that right now we're looking at a glacier that's filling up out of our 180 degree

view we have, we're looking at maybe 10 or 15 degrees of it.

Whereas if we stood in the same place a hundred years ago, it would have filled up about 160 degrees of our view.

You are kidding, 160 degrees of our view?

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