Image of the Week: Glacial Retreat Fills Alaska Lake
The visible impact of climate change on the Earth’s surface is often clearest in the Arctic’s receding glaciers and swelling glacial lakes. Southeastern Alaska’s Harlequin Lake is one of the fastest-growing in North America. These false color Landsat images show the rapidly-retreating Yakutat Glacier, which feeds the lake. Landsat can be used to illustrate the lake’s expansion by more than 15 square miles since 1999. The glacier flowed deep into the lake’s northeastern edge in the summer of 2000, the thicker ice above it shown as deep turquoise. The glacial retreat is starkly apparent a decade later as the icy edge pulls back and the thick turquoise tones give way to reveal clear lines of movement. The upper lake is nearly free of ice by 2020.