Ice Cold

From down in Jackson Hole, that odd name given to the valley of the Snake River, I have looked up at Grand Teton, that highest peak, 13, 770 feet.  Here are two of the many pictures I’ve taken on mornings driving to some trailhead in the mountains.  

But today I wish to zoom in on a feature below the summit of Grand Teton.  You can see that even in October, much ice remains in a canyon there from prior winters.  We had a light dusting of snow a few days ago, but not nearly as much as you see here.  It’s a small remainder, called Teton Glacier, not of the great Pleistocene Ice Age, but from a cool period called the Little Ice Age, 1400 to 1850.  I walked up there and to other glaciated places recently and will lead you on a little trip, if you wish to come, through thousands of years of glaciation.

In the above picture you can see most of my route.  In the lower left just past the trees in the foreground, is Taggart Lake where I met a happy family of moose a few days ago.  Just to the left of Teton Glacier and over the top of the tree covered hill is Amphitheater Lake, my approach yesterday trekking to the glacier.  These places are shown on the map at the right.

Now let’s zoom in from down in Jackson Hole.  Notice what looks like a pile of rocks in front of Teton Glacier.  It looks like an earth-filled dam created by man.  In fact it is a dam and may form a lake, but it is entirely natural.  During the past 40 years, the glacier has retreated about twenty percent.  As it melted, all the rocks that it was carrying down the canyon settled out.  Called a terminal moraine, it may impound water someday to form a lake like Jenny, Taggart or Amphitheater.  Such lakes are called tarns, if anyone cares.  

Climbing up to Amphitheater Lake, I ascended a moraine much larger than the one we see below Teton Glacier.  This moraine is from one of the great Pleistocene glaciations that began 2.7 million years ago and only ended about 15,000 years ago.  Some of these boulders, dropped here by massive ice, are as big as houses.  

Bradley Lake in foreground
Taggart Lake in background
Jackson Hole in distance

Jenny Lake

From the top of the moraine, I looked down on three lakes that I had visited, far below to the east, all formed by moraines like the one I had just climbed. And beyond them is Jackson Hole and the Snake River.

At about 10,000 feet, I reached Amphitheater Lake, a pristine little tarn 

The trail ends here, so I scrambled up a rocky hill to see the moraine below Teton Glacier.

Glaciers are like bulldozers, breaking hard rock, scraping out canyons.  They carry boulders downhill, and fine sand too, but most of the fines get washed down into Jackson Hole, leaving hard rock reminders of how great were the pressures exerted here by ice.  I’m ready for hot coffee now.