Aug 12, 2025
Since 2011, Suicide Basin, a side valley that is dammed by the Mendenhall Glacier, fills with water from snowmelt and rainfall then drains during the summer as a glacial outburst flood. This year, the glacier dammed lake in Suicide Basin, like in 5 other years (2018, 2019, 2020, 2023 and 2024), was full to the top of the Mendenhall Glacier (top of the ice dam) and started to flow down a side drainage channel on August 10th. In past years it has take from 2 to 4 days to begin to drain sub-glacial
Source: NOAA National Weather Service Storm Events Database (event 1292221). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Juneau Borough County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.