Friday, Aug 11, 2006
On Monday, August 7th, Glacier Bay issued an advisory for park visitors planning to be in the Dundas Bay area. This advisory cautions against camping, hiking, boating, or kayaking in the western arm of Dundas Bay due to a possible flooding event that could occur in this arm of the bay at any time.
Researchers, who are studying the natural phenomenon of catastrophic water releases from glacial lakes in southeast Alaska and Canada, have advised park officials that a sudden release of water from Abyss Lake, located on the southeastern edge of the Brady Glacier north of Dundas Bay, may be imminent. Thatâs because another lake on the glacier had a similar release a few days ago.
On August 8th, researcher Denny Capps was flying west across the Brady Glacier when he discovered that Dixon Lake had just about completely drained.
âThere were stranded icebergs a few meters up the shore and there was already turbid water jetting up under pressure at the toe of the nearby glacier lobe,â he reports. âThe Dixon River was ripping!â According to Capps, the lake was about 95% empty and there were standing waves where the river emptied into Dixon Harbor.
What Capps came upon was a âjÃ¶kulhlaupâ â the Icelandic term for a glacial lake outburst flood. A jÃ¶kulhlaup occurs when a lake impounded by a glacier or a terminal moraine dam fails. This can happen due to erosion, a buildup of water pressure, an avalanche of rock or heavy snow, or a massive displacement of lake waters when a section of a glacier breaks off and falls into the water.
Researchers believe that a similar release is likely from Abyss Lake, which experienced jÃ¶kulhlaups during the summers of 1994, 1997, 1998, 2000, 2001 and 2005. These massive and often unexpected outflows caused flooding downstream in the Oscar River, which emptied into the western arm of Dundas Bay. The outflows carried large numbers of uprooted trees (some more than 80 years old), vegetation and a large amount of sediment, all of which were deposited into the waters of Dundas Bay over a very short period of time.
While scientists are unable to predict exactly when the water may be released from the lake, they have noted that the water level in the lake has been rising and a week ago was found to be just seven to eight meters from overflowing out of the lakeâs basin. Based on past releases from the lake, itâs expected that a substantial volume of the lake's water could be released at any time, posing a real hazard to life and property downstream. For that reason, the park is warning the public to stay out of the area until flood potential has passed.
For the most up-to-date information on the status of this area, contact the park's visitor information station at 907-697-2627.