Tongass National Forest

Hubbard Glacier Advance

Issue

Hubbard Glacier, one of the few advancing glaciers in the world, could block the entrance to Russell Fiord near Yakutat, Alaska, creating a large ice-dammed lake. Should that occur, Russell Fiord could fill and eventually drain southward into the Situk River drainage, significantly affecting this important world-class fishery and inundating primarily national forest land, and several Native Allotments. The economy of Yakutat would be affected because the Situk River is the main sport, commercial and subsistence fishery in this community.

Background

In 1986 and 2002, Hubbard Glacier closed the entrance to Russell Fiord, blocking tidal flow between the Fiord and Disenchantment Bay at Gilbert Point. The water level in the new Russell Lake rose to an elevation of 83 feet above sea level in 1986 and 61 feet in 2002. Both times, the ice/moraine dam broke before water overtopped into the Situk River.

Current Situation

Hubbard Glacier retreated to over 1000 feet from Gilbert Point in summer 2005 and remains a considerable distance from closing. The glacier does not start its annual advance until February and USGS will reinitiate monitoring at that time. Glaciologists predict that Hubbard Glacier will again block Russell Fiord; however they cannot predict when this event may happen. Hubbard Glacier has advanced and retreated in the past and there is evidence of a previous overflow event into the Situk River.

Hubbard Glacier may continue this cycle of blockage and dam breakage, as occurred in 1986 and 2002. However, should a stable ice dam form and the lake level rises to an elevation of 135 feet, water would overflow at the southern end of the lake into the Situk River. The Situk River is a world-renowned steelhead and salmon stream. Most impacts of this overflow would occur on National Forest lands and the lands immediately surrounding Russell Fiord lie within Russell Fiord Wilderness.

Because of the cultural, environmental and potentially severe economic consequences of Russell Lake draining into the Situk River, citizens and officials of the community of Yakutat, as well as representatives of several State and Federal agencies, are keenly interested in the behavior of Hubbard Glacier. They have asked for Federal assistance for projects to prevent the overflow from occurring or to mitigate the effects of the overflow. In 2005 the Army Corps of Engineers (ACOE) drafted a reconnaissance report to determine the feasibility of flood damage reduction alternatives to address this issue. The draft report estimated the cost of the feasibility phase at $3.5 million, with construction ranging from $1.8 to $157 million, depending upon alternative. The final report is still in review.

The ACOE and Forest Service are working in partnership to address this issue. The ACOE requested and received $200,000 in Flood Control and Coastal Emergency (FC&CE) funds. These funds have been used for detailed mapping of the glacier and the potentially affected foreland, to assist in defining the likelihood of a closure in the near future, and provide a basis for investigative and initial design work. The Forest Service committed $700,000 for this effort in 2005. The Forest Service and ACOE signed an MOU in fall 2005, followed by a plan of work for these funds. They also prioritized future projects if additional funds become available in 2006 and beyond.

This combined funding will be used for the highest priority tasks. An analysis of the stability of potential ice dams formed by Hubbard Glacier and geotechnical drilling in the moraine where the overflow is predicted to occur are two of the highest priority tasks. Ice dam analysis will help managers better predict when a future closure will happen and how stable the dam will be. Drilling in potential outfall areas is needed to test for soil and bedrock information to determine ultimate feasibility of protective measures. Better topograhpic information using research grade aerial mapping of the moraine and the glacier have been obtained in support of this project, and will be used for detailed mapping and the ice dam stability analysis.

The ACOE is the lead agency for project implementation, and in partnership with NASA, completed the LIDAR flights in fall 2005. The Forest Service is the lead agency for assessing impacts and insuring activities within Russell Fiord Wilderness meet wilderness stewardship principles. The Forest Service completed a minimum tool analysis to minimize impacts on wilderness and then completed NEPA analyses for the drilling in fall 2005. The ACOE completed a reconnaissance trip to Yakutat in December to assess logistics for the drilling. Both the drilling and initial field work to assess ice dam stability will be completed as early as possible in spring 2006, depending on snow conditions and weather.

The Forest Service will continue to work with the community of Yakutat to develop options, mitigation measures and contingency plans. More extensive plans and projects will not occur until additional funding is secured. Currently, the Forest Service has no additional funding for work in FY06. The ACOE has approximately $300,000 for additional work this year, pending approval of the final reconnaissance report.

More Information

Tricia O’Connor, Yakutat District Ranger, (907) 784-3359 or Dave Williams, Project Manager, Alaska District, US Army Corps of Engineers (907) 753-5621.

More about Hubbard, including pictures

Current as of January 2006

USDA Forest Service - Tongass National Forest
Last Modified: November 25, 2007