Photo Challenge – Portage Glacier Cruise, Alaska
May 22, 2018, was our last day of sightseeing before leaving Alaska on the following day. We went on the Portage Glacier Cruise. We were fortunate to have a sunny day for the Denali National Park trip. We had a sunny day again for our glacier cruise. When we arrived at the site of the glacier, the boat stopped, and the captain gave us an orientation of the phenomena of the glacier. Toward the end of the cruise, we had photos taken with the safety ring labeled the company name as our souvenir.
As a point of interest, here are the what and why of blue ice and iceberg.
In the case of oceans or lakes, some of the light hitting the surface of the water is reflected back directly, but most of it penetrates the surface, interacting with its molecules. The water molecule can vibrate in different modes when the light hits it. The red, orange, yellow, and green wavelengths of light are absorbed, the remaining light is composed of the shorter wavelengths of blue and violet. This is the main reason why the ocean is blue.
Small amounts of regular ice appear to be white because of air bubbles are inside them and because small quantities of water appear to be colorless. In glaciers, the pressure causes the air bubbles to be squeezed out, increasing the density of the ice. As it absorbs the colors other than blue, a large piece of compressed ice, or a glacier, would appear blue. https://en.wikipedia.org/wiki/Blue_ice_(glacial)
As we look around the lake, we saw many pieces of the iceberg. Iceberg is a large floating mass of ice detached from a glacier or ice sheet. It floats until it’s carried out to sea. When we see “the tip of the iceberg,” we only see 10% of its mass. We saw one piece of blue iceberg, the mass below the surface must be a large body of ice.
May is the beginning of summer in Alaska, the snow water gushes down countless twisting creeks. If we had gone back in two or three weeks, we would see the beautiful blooms.