Mendenhall flood crest 16.65 ft, barriers shield homes in Juneau

Record floodwaters from the Mendenhall Glacier flooded the Mendenhall River in Juneau early Wednesday, cresting at a height of 16.65 feet and surpassing last year’s record. Officials said the surge, driven by rainwater and snowmelt collecting in Suicide Basin, began earlier in the week and prompted evacuations in parts of the capital city, where barriers were erected to protect hundreds of riverfront homes. While no widespread damage was immediately reported at the peak, authorities warned that high water would persist for several hours and could rise again if conditions worsen.

The floodwaters originate from a basin dammed by the Mendenhall Glacier. A retreating glacier in Suicide Basin created a lake that fills with meltwater each spring and summer. When pressure builds, water overtops or undermines the ice dam and travels into Mendenhall Lake and down the Mendenhall River. Forecasters noted rapid increases in water level in the days leading up to the crest, with rises of as much as four feet per day under favorable conditions. The National Weather Service projected a crest in the range of 16.3 to 16.8 feet, and officials later confirmed the crest at 16.65 feet, a new record.