A remarkable transformation is unfolding in Alaska, where a brand-new island has emerged due to rapid glacial retreat. NASA's latest satellite imagery highlights this striking phenomenon, showcasing the dramatic landscape changes occurring in this icy frontier.

The agency announced that, "Along the coastal plain of southeastern Alaska, water is rapidly replacing ice." The glaciers in this region are retreating at an astonishing rate, leading to the formation of proglacial lakes—one of which has now encircled a small mountain called Prow Knob, effectively creating a new island.

In the summer of 2025, the Alsek Glacier, which once wrapped around Prow Knob, lost contact with it, isolating the roughly 2-square-mile (5-square-kilometer) landmass in the waters of Alsek Lake.

Historically, the Alsek Glacier was a majestic ice formation that once blanketed what is now Alsek Lake. Records from as early as 1894 characterize it as completely entangled in glacier ice. A 1907 report notes its connection to a nunatak—a rocky island surrounded by massive glaciers.

However, from 1948 onwards, the glacier began retreating swiftly, covering distances of up to 5 kilometers (approximately 3 miles) by 1960. This shrinking continued into the late 1970s, culminating in the glacier splitting into distinct ice tongues by 2003.

NASA's newly released images vividly document this retreat, particularly the most recent comparisons between 2018 and 2025. In just seven years, Alsek Lake has expanded dramatically, transforming from a narrow lake bordering Prow Knob to one that completely envelops the mountain.

As temperatures rise, glaciers like Alsek continue to melt, further contributing to the lake's growth. This trend, as NASA cautions, is part of a larger, troubling pattern in Alaska's climate, which, along with other glaciers such as Yakutat and Grand Plateau, has resulted in previously unimaginable lake sizes.

Glaciologist Mauri Pelto highlights that the lakes in this area are among the fastest-growing in the U.S. this century, marking Alaska as a burgeoning lake district. In his words, "This is a unique gem in our nation, forming right before our eyes."