Video
Sperry Glacier Mass Balance Research: A 20-year Legacy
Descriptive Transcript
[Audio description]: A person walks down the steep, snowy margin of a mountain glacier.
[Narrator]: Glaciers are more than melting symbols of climate change.
[Audio description]: Black and white photograph from the Glacier National Park Archives, circa 1942 1965, shows a group of tourists standing on the same snowy glacier margin behind a ranger naturalist.
[Narrator]: Sperry Glacier is an icon for visitors and, perhaps surprisingly, a natural laboratory for scientists.
[Audio description]: Still photographs of researchers on the ice at Sperry Glacier.
[Narrator]: Its relative ease of access allows for consistent scientific study.
[Audio description]: Drawing on a whiteboard depicts a cross section of a mountain cirque, with only the outline of the cross-section and the shape of the mountains drawn in. A ranger gestures to the whiteboard, pointing from the mountain peaks to the lower part of the cross-section.
[Narrator]: In a typical mountain glacier. A body of ice flows from higher elevation to lower elevation.
[Audio description]: Snow appears, drawn in blue at the top of the cirque.
[Narrator]: Snow accumulates in the higher part...
[Audio description]: Zigzagging purple arrows pointing downward. Demonstrate compression with a clock symbol to show the passage of time.
[Narrator]: Compresses, and eventually turns to ice.
[Audio description]: The shape of the glacier appears in blue, filling the cirque about two thirds of the way down the cross-section. There are crevasses and lines in the ice, and the ranger gestures the flowing downward motion of the ice.
[Narrator]: That ice flows downwards and melts out at the lower elevation.
[Audio description]: At the bottom of the glacier. Meltwater is drawn in rivulets that become ponds and then flow into the ground. The ranger points to red plus signs at the top of the glacier where the snow is, then to read minus signs at the bottom where the meltwater is.
[Narrator]: Mass balance measurements track this annual cycle of gains and losses. A checking account for the total water budget of the glacier.
[Audio description]: Timelapse footage from the U.S. Geological Survey shows researchers setting up a steam drill on a snow covered Sperry Glacier.
[Narrator]: Scientists from the U.S. Geological Survey visit Sperry twice a year to collect glacier mass balance data from a network of stakes installed on the surface.
[Audio description]: The glacier is blanketed in snow, with no ice visible.
[Narrator]: In the spring. They measure how much snow accumulated over the winter.
[Audio description]: A USGS graph of Sperry Glacier mass balance appears. The Y axis shows mass balance in meters water equivalent from -12 to 4, and the x axis shows years from 2005 to 2025. The graph legend shows a light blue box that denotes 'winter'. Bars appear across the graph, showing values ranging from about 2 to 5.
[Narrator]: In the fall, they measure how much ice was lost during the summer.
[Audio description]: The graph now shows a light red box in the legend that denotes 'summer'. Bars appear showing summer losses ranging from about -2 to -7. Both winter and summer bars appear together.
[Narrator]: This helps them assess the health of the glacier.
[Audio description]: A researcher sets up equipment on the snow-covered slope of Sperry Glacier.
[Narrator]: 2024 marks the 20th year of mass balance measurements on Sperry Glacier. In some years, there was a net gain.
[Audio description]: Now, the graph legend shows a bright blue box for net gain, and only six bars appear, with values ranging from about 0 to 1.8.
[Narrator] In others, a net loss.
[Audio description]: A bright red box appears for net loss, and 13 bars appear with values ranging from about -0.5 to -3.8. All the values appear on the graph together. A black dotted line appears that denotes the cumulative mass balance value. The line is entirely in the negative values spiking up and down some prior to 2019, and then spiking steeply downward to a value of about -11.
[Narrator]: The glacier has had a negative annual mass balance every year since 2020.
[Audio description]: Sperry Glacier from the side, looking similar to the whiteboard illustration, with glacial ice showing lines and crevasses, flowing downward.
[Narrator]: Glaciers are vital to our ecosystems. Meltwater from mountain glaciers like Sperry provide essential water for plants, animals and people downstream.
[Audio description]: A hiker and two mountain goats walk through a rocky alpine landscape dotted with glacial meltwater pools.
[Narrator]: This rare, long-running record from the USGS helps us understand how glaciers connect to climate, and how fast changes are happening to our cryosphere.
Description
What are glaciers symbols of? Vitality? Curiosity? Power? Loss? How might this change over time?
In 2024, we’re celebrating 20 years of USGS mass balance measurements on Sperry Glacier. That’s 20 years of dedication, data collection, and deliberation. This rare, continuous record helps us understand our glacier’s vital signs and connections to climate.
Duration
1 minute, 29 seconds
Credit
NPS / Renata Harrison & Kylie Caesar
Date Created
11/05/2024
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