National Weather Service United States Department of Commerce

Suicide Basin Monitoring and Current Conditions




Suicide Basin is a side basin of the Mendenhall Glacier above Juneau, Alaska. Since 2011, Suicide Basin has released glacier lake outburst floods that cause inundation along Mendenhall Lake and Mendenhall River.


Current Status: On July 30th Suicide Basin began to drain sub-glacially into Mendenhall Lake after spilling over the top of the ice dam for 5-6 days. The Mendenhall Lake rose almost 6 ft to go above moderate flood stage and crested at 11.53 ft  in the early morning of August 1st. This crest was 2.5 ft above minor flood stage of 9 ft and was the 3rd highest crest of record. The flood waters receded below minor flood stage of 9 ft by 7 pm August 1st. Impacts from this event were some flooded roads, the Mendenhall Lake campground was closed and flooded yards of some residences who live along the river. 

The basin may fill and drain through the rest of the summer. Second releases are typically smaller than the first event of the season. Continued monitoring will be done through August with a few site visits to do some surveys of water levels.  


This event is studied collaboratively by the US Geological Survey / University of Alaska Southeast / National Weather Service / City and Borough of Juneau.


Additional Information available:




Latest Basin Image

Most recent image from the basin, updated at daily to sub-daily intervals (see time-stamp bottom right). The camera is placed at the basin entrance and faces northeast, into the basin. Click on image to enlarge and read basin levels.




Suicide Basin Lake Level
Daily updated graph tracking the lake level at Suicide Basin over the 2020 season (red line). The water level from the 2019 season is included for reference (blue line).





Last Seven Day Time-Lapse

Animated time-lapse sequence, combining daily images. 




2020 Season Time-Lapse Sequence With Vectors

Animated time-lapse sequence including velocity field. Color-coded arrows represent motion of the floating ice in the basin. Latest image with vectors. 






Mendenhall Lake Stage Level


Graph showing the current (blue) and predicted (purple) stage level at Mendenhall Lake. Stage levels are annotated on the left y-axis on the graph. The graph also shows the Mendenhall River discharge (right y-axis), which is derived from the Mendenhall Lake stage level via rating curve.


Once an outburst flood event begins, water levels rise at Mendenhall Lake and Mendenhall River. Drainage initiation at Suicide Basin and water level rise at Mendenhall Lake and River can be offset by several hours.





Water levels on Mendenhall River







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