Glacier variability (1966--2006) in the Wind River Range, Wyoming, U.S.A

Spatial changes in glacier area for 44 glaciers in Wyoming's Wind River Range were estimated through a comparison of historic aerial photography from 1966 to 2006. The total surface area of the 44 glaciers was estimated to be 45.9 +/- 1.6 km2 in 1966 and 28.5 +/- 0.4 km 2 in 2006, a decrease of 42%. Volumes of individual glaciers during the 41-year period were estimated utilizing the Bahr et al. (1997) volume-area scaling technique. The total ice volume lost was estimated to be 0.89 +/- 0.4 km3, which equates to 4.2% and 9.7% of warm season (July-September) streamflow for the Green River and Bull Lake Creek watersheds for the 41-year period. It was also determined that the Dinwoody Creek watershed contributed 12.4% to warm season (July-September) streamflow during the 1989 to 2006 period.;Glacial surface area was also estimated utilizing resampled aerial photography to assess the relationship between area and measurement scale. Aerial photographs were resampled to resolutions of 10 meter, 15 meter, 22.5 meter and 30 meter to represent other satellite image resolutions used for evaluating glacier boundaries. The results show a linear decrease of total glacier area as resolution decreases. When comparing 1 meter resolution to the 30 meter resolution photographs for 1966 and 2006 photos, an average decrease total glacier area of 5% was calculated. It was concluded that high-resolution aerial photography remains the preferred and most accurate source for measuring glacier characteristics.