Outbursts from a Glacier-Dammed Lake 

Andrew G. Fountain (Portland State University)

Outburst floods, or jökulhaups, occur when ice dammed water bodies drain suddenly, usually under the glaciers. These floods are commonly much larger than storm induced floods and consequently are more devastating in their downstream effects: they dramatically reshape stream channels and pose a hazard to human settlements and infrastructure. Understanding timing, size and geomorphic effect of outburst floods requires understanding mechanisms by which impounded water is stored and released. These mechanisms remain poorly studied owing to the unpredictable nature of outburst floods. During the summers of 1999 and 2000 we took advantage of a site with predictable, annual outbursts to launch a systematic, multi-faceted study of outburst floods.

Kennicott Glacier is located in the southwestern portion of the Wrangell Mountains of Alaska (61^o30' N, 143^o W).  The glacier flows from the high peaks of the Wrangells and terminates just before the town of McCarthy.   Glacier-dammed lakes are common along the margin of the glacier, the largest of which is Hidden Creek Lake, about 1.5 - 2 km²  (Rickman and Rosenkrans, 1997). 

The lake drains annually, sometime between mid-July and September since 1911 when records began.  The lake drains in about 1-2 days time, and flows under the glacier for about 12 miles where it appears at the terminus of the glacier as the Kennicott River.

Kennicott Glacier, 27 August 1969.  Photo by the U.S. Geological Survey,

The Project: The project has 3 distinct goals. The first goal is to measure the flexure of the ice-dam in response to the lake filling (Joe Walder, USGS). This will aid in determining the position of the hydraulic seal. The second goal is to monitor the changing subglacial hydraulic condition as the location of the seal changes and as the lake makes a hydraulic connection to the subglacial drainage system (Andrew Fountain, PSU). The third goal is to measure the flood hydrograph from the glacier and assess resulting downstream geomorphic changes (Suzanne Anderson, UCSC).

The ice dam can be seen at right, where the glacier ice meets the waters of Hidden Creek Lake.  The odd appearance of the lake is due to the floating ice calved off the glacier.

Photo by the U.S. Geological Survey, Project Office Glaciology, 6 August 1975.

Team Members: 

Portland State University  

• Dr. Andrew G. Fountain, Principal Investigator
• Mr. Donald Lindsay, Graduate Student
• Ms. Michelle Cunico, Graduate Student
• Mr. Robert Schlichting, Vancouver School of Arts and Academics, Vancouver, WA
•       Robert's diary of the 1999 field season: http://tea.armadaproject.org/tea_rschlichtingfrontpage.html

          Assisted by:

• Dr. Joel Harper, University of Wyoming
• Dr. Steve Malone, University of Washington
• Mr. Andrew Malm, undergraduate student at St. Olaf College supervised by Dr. Robert Jacobel

US Geological Survey

• Dr. Joseph S. Walder, Principal Investigator
• Mr. Dennis Trabant

University of California at Santa Cruz

• Dr. Suzanne P. Anderson, Principal Investigator
• Dr. Robert Anderson, Field Team Leader
• Erin Kraal, Graduate Student
• Christy Swindling, Undergraduate Student
• Sharon Longacre, Undergraduate Student

National Science Foundation

    This project has been funded through the National Science Foundation Office of Polar Programs; grant numbers           OPP9812945 and OPP9912129.

1994 Lake Drainage:  In late July of 1994 Joe Walder and Carolyn Driedger made preliminary measurements of Hidden Creek Lake.   They left a time lapse camera and captured the drainage of the lake and response of the ice dam.   VIDEO NOT WORKING 

1999 Lake Drainage:

•     Photos of the field work:   VIEW

•     A time-lapse video that captured the drainage of the lake.   VIEW

2000 Lake Drainage:

•     Photos of the field work:    VIEW

•     A time-lapse video that captured the 2000 drainage event:      VIDEO NOT WORKING