Juneau's Suicide Basin refills fast as second release remains possible

Suicide Basin, the glacier-dammed lake above Juneau that sent the Mendenhall River into major flooding in August, is filling back up. The National Weather Service in Juneau says a second release could come at any time, though none is forecast and no flood watch or warning is in effect.

The basin has regained about 70 percent of the depth it lost when it drained in mid-August, according to the weather service. That release pushed the river past major flood stage on Aug. 13 and led to evacuation advisories for about 1,900 homes.

A second, smaller release has come in each of the past two falls. In October 2024, the river crested at 10.77 feet, a moderate flood. In September 2025, it reached 9.63 feet, a minor flood. The state said Sept. 24 that a full release now would bring minor flooding.

The river was at 2.2 feet Sunday morning, with 3.94 feet forecast for Monday night. Here is what higher levels would mean:

• 9 feet (flood stage): water reaches Mendenhall Lake Campground.

• 10.5 feet: the campground is evacuated.

• 11 feet: some yards on View Drive and Meander Way flood.

August's flood was the fourth major one in four years and the smallest of them, cresting at 14.71 feet. The 2025 crest of 16.65 feet remains the highest in records dating to 1966. Gov. Mike Dunleavy declared a state disaster after the City and Borough of Juneau and the Central Council of the Tlingit and Haida Indian Tribes of Alaska jointly asked for help on Aug. 12.

Juneau held a debrief for affected residents Sept. 16 and is taking responses to a resident survey through Oct. 16. The weather service posts basin and river updates at weather.gov/ajk.