DENVER (AP) -- The Columbia Glacier near Valdez is retreating so quickly that tour boats should be able to work their way up to its face within the next decade or so, a scientist says.
A University of Colorado researcher said Monday that the glacier is shrinking as much as 100 feet per day. ''That's really ripping along,'' Tad Pfeffer said.
The Columbia Glacier is a massive river of ice flowing from the Chugach Mountains into a side channel of Prince William Sound. It has been rapidly sliding on its bed. The front of the glacier is breaking off icebergs, which can pose a threat in shipping lanes.
The glacier most likely will make a hasty retreat up the fjord or thin quickly and disintegrate abruptly, Pfeffer said.
And when it does disintegrate, ''it should be quite a spectacular sight,'' he said. Tour boats -- in 10 to 50 years by the best calculations -- should be floating where the glacier is sitting today.
The scientist doesn't blame global warming, however, because other nearby glaciers aren't doing a similar disappearing act. Instead, Pfeffer thinks something complex is going on inside the glacier that's causing it to calve icebergs at an impressive rate.
''The loss of ice primarily is due to calving rather than to thermal reasons,'' such as global warming, Pfeffer said. ''It's hard to get people to look beyond the glacier shrinking.''
The rapid flow of the glacier -- considered one of the world's fastest glaciers -- coupled with its thinning and stretching has caused icebergs to break off. So far, most of the larger icebergs are jammed against an underwater shoal of rocks and don't drift into Prince William Sound.
People shouldn't be alarmed at the Columbia's behavior, Pfeffer said. It's just the last of Alaska's 51 tidewater glaciers to retreat.
The tips of tidewater glaciers rest in several hundred yards of sea water. That means a small amount of water trapped between the glacier and its bed may float the glacier and speed its retreat.
''In the 1800s, Glacier Bay, where the cruise ships go now, was full of ice,'' Pfeffer said. ''What is happening to the Columbia is what happens to these fjords.''
The Columbia Glacier was named by Captain Cook as he explored Prince William Sound in 1890. It has retreated and advanced many times before. Cook was greeted by a Columbia in full advance, which it did until about 1982. Since then, the 435-square-mile glacier has retreated more than seven miles.
Pfeffer is the chief author of a paper about the glacier that was published last week in Eos, an international scientific newsletter of the American Geophysical Union.
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