HR: 0800h
AN: C41A-0058    [Abstracts]
TI: Near Realtime Monitoring of Tidewater Glacier Advance and Retreat: Hubbard Glacier, Southeast Alaska
AU: * Finnegan, D C
EM: David.Finnegan@erdc.usace.army.mil
AF: US Army Engineer Research and Development Center, Cold Regions Research and Engineering Lab, 72 Lyme Road, Hanover, NH 03755, United States
AU: Lawson, D E
EM: daniel.e.lawson@erdc.usace.army.mil
AF: US Army Engineer Research and Development Center, Cold Regions Research and Engineering Lab, 72 Lyme Road, Hanover, NH 03755, United States
AU: Hanlon, G
EM: greg.hanlon@usace.army.mil
AF: US Army Corps of Engineers, New England District, 66 Virginia Rd, Concord, MA 01742, United States
AU: Kalli, G
EM: george.kalli@usace.army.mil
AF: US Army Corps of Engineers, Alaska District, PO BOX 6898, Anchorage, AK 99506, United States
AB: Tidewater glaciers advance and retreat seasonally as part of the well-documented tidewater glacier cycle. Quantitative factors that influence tidewater glacier activity are often difficult to capture. The accurate collection of such data is a key to better understanding this cycle. In this paper, we describe the results of current research at Hubbard Glacier to quantify realtime glacier terminus activity using high-resolution ranging measurements and local meteorologic conditions. Hubbard Glacier is the largest non-polar tidewater glacier in the world. It encompasses an area of 3500 sq km and flows 120 km from the flanks of Mt Logan (5959 m) in the Wrangell St. Elias Mountains (Canada) to sea level where its terminus widens to ~11.5 km. In contrast to most glaciers in Southeast Alaska, Hubbard Glacier continues to advance and thicken and is predicted to continue for the foreseeable future. Our data provide unique, high-resolution (4 times daily) measurements of ice margin motion along a section of the terminus near Gilbert Point. Gilbert Point is the location of past ice dams formed by Hubbard Glacier (1986, 2002) both of which failed and generated massive outburst floods. This location is critical to understanding the potential for future ice dam formation by Hubbard Glacier. Preliminary results of monitoring since late 2006 indicate variable rates in ice motion within periods of overall advance and retreat. A seasonal advance of the glacier occurred from March to mid-June 2007, advancing 280 m in 98 days at an average of 2.85 m/day, but with daily average rates occasionally as high as 10 m/day. A period of retreat began in mid-June with a large calving event that removed 60 m of ice from the terminus in less than a day. This seasonal retreat has continued with retreat rates varying from 1.11 m/day in the first 45 days to 2.39 m/day between August 1st and 30th, 2007.
UR: http://www.GlacierResearch.org
DE: 0720 Glaciers
DE: 0774 Dynamics
DE: 0794 Instruments and techniques
SC: Cryosphere [C]
MN: 2007 Fall Meeting