In the southeastern reaches of Alaska, landscapes are being dramatically reshaped as ice gives way to water.
Recent images released by the NASA Earth Observatory reveal striking changes to the region's proglacial lakes, formed as glaciers retreat and meltwater pools at their fronts.
Over the past four decades, three lakes—Harlequin, Alsek and Grand Plateau—have grown at an astonishing pace, transforming the region into a burgeoning "lake district."
The trio of glaciers feeding these lakes—Yakutat, Alsek and Grand Plateau—descend from Alaska's inland mountains to the coastal plain southeast of Yakutat borough.
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Glaciers are massive, slow-moving rivers of ice formed from compacted layers of snow that accumulate over centuries, flowing under their own weight and reshaping the landscapes they traverse.
An analysis by glaciologist Mauri Pelto of Nichols College highlights the dramatic retreat of these glaciers between 1984 and 2024.
During this time, Yakutat Glacier's main arm retreated 4.3 miles, and Alsek Glacier's northern and southern arms retreated 3.3 miles and 3.4 miles, respectively.
Grand Plateau Glacier's northern arm saw the most significant change, retreating 4.8 miles.
These changes were captured in a pair of satellite images from the Landsat 5 and Landsat 8 satellites in the summers of 1984 and 2024, revealing how water now fills the void left by ice. Together, the three lakes almost doubled in size over the 40-year period.
In 1984, the lakes spanned about 50 square miles. By 2024, they covered 90 square miles—an area larger than New York's Seneca Lake, one of the Finger Lakes also carved by ancient glaciers.
"The lakes that are forming in this region are immense, starting at the mountains and spreading toward the coast, making this a new lake district that is unique in our nation," Pelto said in a statement.
Pelto suggested this lake system could represent the fastest-growing collection of lakes in the U.S. in this century, reflecting the accelerated retreat of Alaska's glaciers due to climate change.
The lakes are not only expanding but also undergoing noticeable transformations.
Alsek Lake, for instance, appears much bluer in the 2024 image compared to 1984. This shift suggests that the lake is receiving less "glacial flour"—fine-grained sediment carried by meltwater streams, according to a NASA Earth Observatory article.
As sediment levels drop, the lake's water will continue to darken, allowing more light to penetrate and potentially fostering aquatic life and fishery development.
The pattern is one that is repeating across Alaska and the Arctic more broadly.
According to the National Park Service, glaciers within Alaska national parks shrank by 8 percent between the 1950s and the early 2000s. This pace ticked upward, with 13 percent lost from 1985 to 2020.
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