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Flood — Juneau Borough, AK

Aug 5, 2023

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 3 other years (2018, 2019 and 2020), was full to the top of the Mendenhall Glacier (top of the ice dam) and started to flow down a side drainage channel. After about 7 days, Suicide Basin began to drain sub-glacially. Mendenhall Lake started to rise fro

Source: NOAA National Weather Service Storm Events Database (event 1127010). Narrative written by NWS staff at the time of the event.

Flood Risk Context for Juneau Borough, AK

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.

View Juneau Borough County flood data →

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Flood$5.9M damage

Juneau Borough, AK · 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.

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Flood$6.7M damage

Juneau Borough, AK · Aug 5, 2024

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