Melting glacier creates a new island in Alaska, satellite images show

A melting glacier in southeastern Alaska has birthed a brand-new island in the middle of a growing lake, according to recent images captured by NASA satellites.

The 2-square-mile island is a small mountain known as Prow Knob, which was once surrounded by a frozen expanse known as the Alsek Glacier. As the glacier thawed and retreated, meltwater flooded the region.

This summer, satellites observed Prow Knob as it was finally stranded as a lone landmass within the expanding Alsek Lake.

This type of transformation is a hallmark of climate change, as rising temperatures and melting ice reshape coastlines around the world and sometimes alter landscapes in dramatic ways.

NASA’s Landsat 5 satellite snapped images of Prow Knob in July 1984, showing that part of the mountain’s western perimeter touched the lakeshore. The rest, however, was enveloped by the mass of ice that made up the Alsek Glacier.

Over the next four decades, aerial images documented the steady, eastward retreat of both the Alsek Glacier and another ice mass to the south called the Grand Plateau Glacier. As both glaciers melted, Alsek Lake grew significantly, filling in the void left by the Grand Plateau Glacier and gradually overtaking the ice that once surrounded Prow Knob.

This summer, NASA’s Landsat 9 satellite observed the last bit of ice pulling away from Prow Knob, officially turning the landmass into an island.

The space agency estimated that the separation occurred sometime between July 13 and Aug. 6.

In the early 20th century, the Alsek Glacier was far more extensive, reaching all the way to a landmass known as Gateway Knob, located roughly 3 miles west of Prow Knob, according to glaciologists. Since 1984, the glacier has retreated more than 3 miles, according to NASA.

Alsek Lake, in turn, has nearly doubled in size since 1984, growing from around 17 square miles to almost 30 square miles. The runoff of meltwater into the glacier basin forms what is known as a “proglacial lake.”

Additional melting is expected in the coming years, NASA said, particularly now that the ice has detached from Prow Knob and is thus less stable.

This article was originally published on NBCNews.com