Glacier Bay
After picking up our Park Rangers, Steve and Fran, from the dock at Gustavus, we headed into Glacier Bay National Park on a cool and misty morning. Our first wildlife viewing opportunity was at the South Marble Islands, which is a nesting area for thousands of birds and a haul out for dozens of sea lions. This is a good place to observe habitat stratification. Kittiwakes have taken over the lower part of the islands near the water. Above them in burrows are the puffins and gulls occupying the view properties on the top. Puffins were a continuing source of amusement with their wings beating frantically just to stay airborne. Fortunately they swim underwater a lot better than they fly.
Moving up the fjord we stopped at Tidal Inlet where we saw a slide scarp high on the mountain. To geologists, this is a warning that a sudden giant rock fall might happen here in the future. If so, a giant wave, as much as 300 feet high could be generated in the inlet. Around the corner was Gloomy Knob, a dark grey mass of marble that is a favorite hangout for mountain goats. Today we saw six, including a kid that was probably born this spring. After watching them adroitly scale near vertical cliffs, we weren’t surprised to learn that their feet have adaptively evolved for climbing on rocks.
At very end of the fjord in Tarr Inlet we saw two very different looking glaciers. The Margerie was mostly a brilliant blend of white and blue with a few dark stripes for contrast. The Grand Pacific was mostly a dour dark brown—covered by rocks from moraines and avalanches. The Margerie presented a 200 foot high almost vertical wall of ice at its terminus, whereas the Grand Pacific had a much more gentle slope overall. The low slope is due to a slow rate of calving and a fairly rapid thinning of the Grand Pacific.
The Lamplugh Glacier is noted for its intense blue color, but even more impressive is the melt water stream that literally erupts from the front face of the glacier near its base. A reasonable estimate of the rate of flow is around 3000 cubic feet per second, which is greater than a lot of streams in SE Alaska. The source is mostly melt water, which percolates down through the glacier and cuts channels through the ice creating subsurface rivers.
After dinner we finally got a chance to hike onshore through a hemlock and cedar forest that has grown during the 200+ years since the Grand Pacific Glacier started melting back from the mouth of Glacier Bay in the late 1700’s. So what we have seen today is the progression from the barren rock and till left behind by a melting glacier to the magnificent old growth forest that occupies the land today. This is a lesson in just how rapidly our habitat can change that should not be soon forgotten.
