Chasing Ice- The Movie
In June my students and I watched James Balog's documentary, Chasing Ice. If you haven't seen it, we recommend it; it is available to rent from Amazon. The photography is stunning, his passion is inspiring and the message is urgent. I don't want to spoil it, so I'll leave it at that, but I will say that I had my students complete a writing piece after the movie and every student was changed by his story. Today I felt like I had my own experience "Chasing Ice".
Chasing Ice- Attempt Number One
We began by hiking upstream, following the glacial meltwater backwards. These braided streams are typical of glacial meltwater systems or any river system carrying a large sediment load.
The braided stream- glacial meltwater. Why do you think it looks like chocolate milk?
It was a beautiful hike but we needed to either cross the stream or climb higher along the western side to access the glacier. There was no safe crossing; it was too deep and the current too fast. The "ground" beneath us quickly changed to loose rocks. The rocks were about as big as a laptop computer. As we walked on them they shifted and together our steps created much clanging noise. Eventually these rock piles became whole rock mountains and they rose so sharply that we were in danger of rock slides and turned around.
We hiked over huge piles of loose rocks. Where do you think these came from?
The loose rocks formed huge, steep mountains. Anyone know what this is called? The gray stuctures toward the bottom are blocks of ice.
So, I was disappointed. Nobody said anything, but I think some of the students were also disappointed that we didn't go all the way to the glacier. We stopped for lunch and took in more wonderful scenery hiking back to the guesthouse.
Chasing Ice- Attempt Number Two
When we got back the afternoon was still young, so some of us decided to go for another try, heading along the left of the stream instead of the right. This time we found a crossing across a side spur of the stream, making fording the remainder less daunting (although challenging enough to keep it exciting). We quickly headed back up and over the steep, muddy, loose rock piles. Soon the glacier came into view. Wow! It was like I had walked into my own "Chasing Ice"
Me, chasing ice.
Glaciers
Valley glaciers melt into streams rather than calving into water like tidewater glaciers. How much ice must be melting to create this raging stream? What part of the glacier do you think is melting the most? Notice how the turbulent water undercuts the ice from below. Where did all the rocks come from? Isn't it beautiful? These are questions to think about along with something else. The reason we couldn't access the glacier via the first route is because it no longer ended in the expected place. It had moved farther back into the valley. It has receded. It is normal for glaciers to melt in the summer, but its recession rate and deflation (how quickly it has moved back and shrunk) is not normal. This is what James Balog documented in "Chasing Ice" and now I have seen it for myself.
What part of the glacier do you think is melting the most?
The water is undercutting the ice. Why is the ice so dirty?
This glacier has retreated since the last time an REU group was here.
Isn't it beautiful?
Take A Closer Look
Steven H. from Avocado Elementary asks, "How do the glaciers move? Is it because of the currents or do they just move on their own?"
How do the glaciers move? Is it because of the currents or do they just move on their own?
Great question, Steven. Glaciers creep downhill because of the force of gravity. But they have help from a few other things. The ice at the bottom of the glacier can melt due to increased pressure, friction and geothermal heat. Streams form under glaciers. This lubricates the glacier and increases the rate of motion. Thanks for the question!
Put your answers to the questions I asked (in the picture captions) or any comments in the "Ask the Team" space to the right. Let me hear from you! Are you out there? And...
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