Jul 31, 2020
Throughout spring and the first part of the summer Suicide Basin, a side valley that is dammed by the Mendenhall Glacier, filled with water from snowmelt and rainfall. In the afternoon hours of July 30th visual reports showed signs of the basin beginning to drain sub-glacially as the dam was starting to fail. This is after a few days of water overtopping the ice dam. The Mendenhall Lake gage started to show this inflow of water from the basin through the evening hours and by the morning of the 3
Source: NOAA National Weather Service Storm Events Database (event 915697). 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.