|In the morning we sailed through Icy Strait and entered Bartlett Cove which begins Glacier Bay National Park. We sailed northwest up the Bay to the extreme northern end. There we sat still in the water just off the face of Margerie Glacier for more than an hour while the ship was slowly rotated in place so everyone could have a good view. This also gave us a clear view of Grand Pacific Glacier, one of the largest in Glacier Bay. It has a different appearance because it's face is "dirty" from all the debris picked up during a long trip over land to reach the sea. That journey begins in Canada and ends in the United States at Glacier Bay.
Margerie Glacier passes over a cliff just as it meets the sea. Because this glacier moves relatively rapidly, sometimes up to 12 feet per day, ice frequently breaks off when it is pushed over the edge and no longer has any support underneath. The breaking off of the ice is called calving. Sometimes the ice comes off in large pieces, and sometimes the "calves" are much smaller. When a large piece breaks away there is frequently a loud report, like a canon shot. We were able to hear that sound as the ice broke away and fell into the sea.
The water under the ship, as we sat just off Margerie Glacier, is extraordinarily deep. At one point we were told the water under the keel was more than 900 meters, or about 1,000 feet, deep. That's why cruise ships come to this place and are able to sit so close to the face of the glacier without any risk to the vessel. The deep narrow channel we used to enter Glacier Bay, and the deep water we floated in are the results of ancient glaciers flowing down to the sea and using their unbelievable weight and force to carve deep grooves into the underlying rock.
As we left Margerie Glacier we could see Lamplugh Glacier off in the distance. It's known as the blue glacier because at times, when the sun hits its face just right, the glacier takes on a blue cast.
There are also "hanging glaciers" on the sides of the mountains at Glacier Bay. These glaciers are not called "tidewater glaciers" like the ones that have reached the sea. They might or might not ever reach the ocean. Some of them are growing, and some are shrinking. What happens will be very much dependent on such things as annual snow fall in the coming years and temperature changes. Whatever happens will be slow. It can take thousands of years for significant glacial changes to occur.