Overview

• NASA’s Landsat 9 imagery indicates the final ice separation occurred between July 13 and August 6, 2025.
• Alsek Lake has expanded from about 45 to 75 square kilometers since 1984 as the glacier retreated.
• Prow Knob measures roughly 2 square miles and sits within Glacier Bay National Park and Preserve, which contains over 1,000 glaciers.
• Glaciologist Mauri Pelto says islands of this scale revealed by glacier retreat are rare in Alaska but could become more common as warming continues.
• Recent imagery shows bluer lake water that suggests reduced fine sediment, and scientists warn of increased calving and related geohazard risks.