Map of Suicide Basin

As the smaller Suicide Glacier in Juneau, Alaska rapidly receded away from the large Mendenhall Glacier, it left behind a barren, rock- and iceberg-filled basin. Rainwater, ice, and glacier meltwater accumulate in the basin, cupped between the Mendenhall Glacier and the bare mountain. When the water level reaches a certain threshold, it builds up enough pressure to force its way underneath the Mendenhall Glacier, draining into the Mendenhall Lake in a glacial outburst flood. As the lake overflows, the floodwaters inundate roads and homes, eventually making their way down the Mendenhall River and to the ocean.