Annual Assessment of North Cascades Glaciers Finds ‘Shocking Loss’ of Volume

The summer of 2019 found the North Cascade Glacier Climate Project in the field for the 36th consecutive summer monitoring the response of North Cascade glaciers to climate change. This long term monitoring program was initiated partly in response to a challenge in 1983 from Stephen Schneider to begin monitoring glacier systems before and as climate change became a dominant variable in their behavior.

The field team was comprised of Clara Deck, Ann Hill, Abby Hudak, Jill Pelto, and myself. All of us have worked on other glaciers. The bottom line for 2019 is the shocking loss of glacier volume.

Ann Hill, University of Maine graduate student observed, “Despite having experience studying glaciers in southeast Alaska and in Svalbard, I was shocked by the amount of thinning each glacier has endured through the last two and a half decades.” 

Glaciers are typically noted as powerful moving inexorably. Clara Deck, University of Maine MS graduate, was struck by “the beauty and fragility of the alpine environment and glaciers.” Fragile indeed in the face of climate change.

Abby Hudak, a Washington State graduate student, looked at both the glacier and biologic communities as under stress, but glaciers cannot migrate, adapt, or alter their DNA.

Easton Glacier, Mount Baker. Terminus has become thin and uncrevassed as a rapid retreat of 15 meters per year continued, with 405 m of retreat since 1990.

Over the span of 16 days in the field, every night spent in the backcountry adjacent to a glacier, we examined 10 glaciers in detail. All glaciers are accessed by backpacking. The measurements completed add to the now 36-year-long database that indicate a ~30 percent volume loss of these glaciers during that period (Pelto, 2018).

Here we review preliminary results from each glacier. Each glacier will have a mass balance loss of  1.5 -2.25 m, which drives continued retreat.  Columbia and Rainbow Glacier are reference glaciers for the World Glacier Monitoring Service, with Easton Glacier joining the ranks later this year.

Below and above is the visual summary. Specific mass balance and retreat data will be published here and with WGMS after October 1.

Easton Glacier icefall at 2,200 meters typically has 1.8 m w.e. at the end of the summer, this year it will be 0 m. The overall mass balance will be ~2 m of loss.
Deming Glacier, Mount Baker has now receded over 700 m since our first visit 35 years ago.

On Lower Curtis Glacier, a key accumulation source, the NE couloir now shows bedrock. Overall by summers end ~25 percent of the glacier will retain snow cover, far short of what is needed to maintain its volume.
The Lower Curtis Glacier terminus continues to retreat at 8 meters/year, but thinning and slope reduction has been more notable.
In early August, the majority of Sholes Glacier has lost its snowpack. The thin nature of the terminus indicates the glacier is poised for continued rapid retreat that has exceeded 15 meters per year during the last 7 years.
Runoff assessment confirmed ablation stake measurement of 11 centimeters of ablation/day from 8/6-8/8 on Sholes Glacier.
High on Rainbow Glacier, there are still plenty of regions lacking snow cover instead of a thick mantle of snowpack.
Rainbow Glacier was awash in meltwater streams (see video). This area should have 1 meter of snowpack left. Rainbow Glacier has retreated 650 meters since 1984.
Just getting to each glacier does involve overcoming various miseries.

To see more photos of the 36th annual North Cascades monitoring project, check out the Mauri Pelto’s original post on From a Glacier’s Perspective, a blog published by the American Geophysical Union.

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