Friday, September 23, 2011

A Day cruising Glacier Bay

Today was spent learning about an environment in which I have no experience – Glacier Bay National Park and Preserve. As we continued north along the inside passage this was the next major ecosystem in South east Alaska situated adjacent to the Canadian border.

Glacier Bay is 65 miles long from the entrance at the narrows and as we entered the bay National Park Rangers embarked the ship an spent the day with us talking through the history, geology and ecology of the area. They are extremely knowledgeable and experienced and I was particularly impressed with one of the rangers who had spent many summer vacations (from her teaching job) kayaking each of the many glacial inlets.

Glaciers are living evolving structures and don’t allow for easy categorization. While many are indeed shrinking (most in fact) some continue to grow even now depending on the microclimate – snowfall and temperature.
In 1680, Glacier Bay did not exist but rather there was a broad valley on which Tlingit people lived with a glacier at its head.
The little Ice Age of the 1700s saw the rapid extension of the glacier to a maximum in 1750 forcing the local population to move and gouging out the contours of the present bay.
By 1795 the explorer George Vancouver documented that the glacier had retreated 5 miles back into the newly created bay; John Muir, 100 years later found a bay 40 miles longer and today tidewater glaciers are 65 miles up the bay.
Glaciers consist of ice, rock that has become incorporated with movement and water. The weight of the ice together with the movement and the abrasive force of the rock carves a path through any but the most resistant rock and as the glacier is calved or melts rock and soil are deposited
 The ship prepared us well for a day outdoors - that was where it was clearly best to see everything

They also provided superior cold weather gear for intrepid Alaska explorers
The scenery was spectacular - again I cant get used to the natural beauty 

We saw two of the most impressive but very different glaciers today – the Grand Pacific Glacier – brown in color and little in the way of blue ice because of the rock content and the famous Margerie Glacier – 250 foot tall with clear layering of rock and ice dating back hundreds of years.

We also passed valleys carved out by glaciers at different stages of recovery – at first covered in mosses and lichens, the bushy plants and grasses and finally with trees, eventually becoming forested. The shape of the valley and the rocky debris (scree) tell the story though.

After cruising the bay we passed whales, sea otters and sea lions; dropped off the park rangers and were on our northward way again.
Next stop college fjords.

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