Sawyer Glacier Alaska in False Color Sentinel images from Sept. 12, 2022 and May 23, 2023. Note the the calving face in 2022 between the yellows arrows has become bare ground by May 23, 2023. TA=Tracy Arm

Sawyer Glacier, is an Alaskan glacier where the retreat has long been viewed by many visitors. It is one of  the two primary glaciers that calves into Tracy Arm fjord, that is often visited by cruise ships. The 3.3 km retreat from 1961-2022 has made approach to the actual terminus difficult for larger cruise ships (Lindblad Expeditions, Allen Marine Tours or Holland Amreica) . The terminus of the glacier was almost to the main arm of the fjord in 1961, USGS map below.  Landsat images from 1990 to 2013 indicate retreat from the 1990 terminus, red arrow, to the 2013 terminus, yellow arrow is 2800 km, 120m/year. From 2013-2022 the retreat has been slower with ~500 m retreat, 50 m/year.

Sawyer Glacier retreat from 1990 to 2013 in Landsat images. Yellow arrow=2013 terminus; Red arrow=1990 terminus; purple arrow

Sawyer Glacier retreat from 1990 to May 10, 2023 in Landsat images. Green Arrow=2023 terminus Yellow arrow=2013 terminus; Red arrow=1990 terminus; purple arrow

From 1874 when John Muir first enthused about the calving glaciers of this fjord through 2022 their has been a calving front in the fjord.  This was true as the cruise ship season ended in 2022. False color Sentinel images in Sept. and Oct. 2022 indicate a calving front that is 250 m wide. False color Sentinel images on May 10 and 23, 2023 indicate the front of the glacier entirely resting above fjords waters.  High tide may touch the glacier at ts southernmost point.  Melkonian et al (2016) observed a rapid thinning of the Stikine Icefield of -0.57 m/year from 2000-2014. This loss has been driving by rising snowlines.  Pelto (1987) reported a snowline of 1125 m the 1980’s, that now averages over 1300 m. The retreat here is similar to that of nearby Dawes and South Sawyer Glacier. This loss of iceberg  production will impact harbor seals as they prefer icebergs to haul out on. (Alaska Department of Fish and Game ).

May 10 and 23, 2023 Sentinel images indicating bare ground across entire terminus front.

Sawyer Glacier Alaska in False Color Sentinel images from Sept 12, 2022 and Aug. 7, 2016. Note the the calving face in 2016 and 2022 between the yellows arrows.

USGS 1961 topographic map showing location of terminus in 1961 and 2003.


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