Ben Speiss, USA Today, Aug. 11, 1998
The Columbia Glacier in Alaska's Prince William Sound is disgorging more than one million tons of ice a day into shipping lanes outside Valdez, posing a threat to the more than 600 tankers laden with Alaskan crude oil that traverse the lanes each year, USA Today reports.
The Columbia Glacier has retreated about six miles since 1980, dropping 100 tons of ice into the ocean every second during the months of August and September. Icebergs and smaller ice chunks, which range from less than 1,000 tons to 50,000 tons "prowl" into shipping lanes on the wind and tide posing safety issues for the tankers. The Exxon Valdez in 1989 altered its course to avoid ice and plowed into a reef spilling 11 million gallons of oil.
At times oil companies have voluntarily restricted shipping into Valdez to daylight hours, and in 1984 they requested radar to help detect the ice, but were turned down by the Coast Guard.
Currently the only ice detectors are captains and crew who are required to report ice conditions to the Coast Guard when passing through Valdez.
The Prince William Sound Regional Citizens Advisory Council in 1996 commissioned a study of the glacier to help predict peak ice flow into the shipping lanes. At a progress report to the US Arctic Research Council last week, researchers shower how they have mapped the glacier using research by the US Geological Survey.
Meanwhile, the Columbia Glacier could continue to retreat for another 30 years, according to glaciologist Wendell Tangborn, who presented the report. "Strangely enough," oil industry and glacier experts expect the both tanker traffic from the North Slope oil field and the glacier's decline to last about 30 years
(Ben Spiess, USA Today, 8/11/98).