A water basin in Alaska is overflowing its ice dam, the Mendenhall Glacier, and flooding the state capital, Juneau. Experts expect the likely record-breaking event to peak today, and officials have asked residents in parts of the city and borough to evacuate.

The flood doesn’t come as a surprise. Years ago, a small glacier on the other side of Mendenhall Glacier—which is just 12 miles (19 kilometers) from Juneau—receded and left a basin in its wake, according to the Associated Press . Since then, rainwater and snowmelt fill the basin during the warm months of the year, with water sometimes leaking under or around the Mendenhall Glacier into Mendenhall Lake on the other side, then into the Mendenhall River and downstream.

This mechanism has caused problems since 2011. 2023 and 2024 saw

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