C21F-03
Early 21st Century Area and Mass Change of Alpine Glaciers in Western Northern America
Tuesday, 15 December 2015: 08:30
3009 (Moscone West)
Brian Menounos1, Ben Mauri Pelto1, Andrew G Fountain2, Alex S Gardner3, Matthew J Beedle1, Jon L Riedel4, Shawn J Marshall5, Michael N. Demuth6, Robert Vogt1, Mauri S Pelto7 and Chris McNeil8, (1)University of Northern British Columbia, Prince George, BC, Canada, (2)Portland State University, Portland, OR, United States, (3)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (4)National Park Service, Marblemount, WA, United States, (5)University of Calgary, Calgary, AB, Canada, (6)University of Saskatchewan, Centre for Hydrology, Saskatoon, SK, Canada, (7)Nichols College, Dudley, MA, United States, (8)United States Geological Survey, Denver, CO, United States
Abstract:
Exceptionally warm, dry conditions in the Pacific Northwest and southern latitudes of western Canada commenced in 2013 and continue today. The winter of 2014/2015, for example, saw freezing levels in the Cascade Mountains rise to elevations not seen in the instrumental record. Record thin snow packs have similarly occurred for many regions with some mountains lacking any measurable snow cover at the end of the accumulation season. Our study objectives are twofold: First, we quantify recent changes in glacier area and mass and evaluate these changes against longer term records from the region. Second, we address the importance of extreme mass change events for long-term glacier fluctuations and mass change. Our data are derived from air- (LiDAR and 1-m resolution aerial photographs) and space-borne platforms (Landsat 8, WorldView) in addition to direct mass balance measurements of key glaciers throughout the region. WorldView stereo imagery is currently being acquired for select glaciers where we routinely fly LiDAR surveys. Use of varied methods for mass and area change assessment allows us to quantify methodological biases and uncertainties. Long term trends in glacier shrinkage are controlled by warming air temperatures whereas precipitation is an important factor in decadal variability. Glacier retreat, particularly in maritime environments, slowed during the period 2005-2013 relative to retreat rates observed during 1985-2005. Retreat rates for the past two years, however, have strongly accelerated. Our results from Washington, British Columbia and Southeast Alaska indicate that 2014/2015 will be a record year of glacier mass and area loss for the region.
