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

Suicide Basin above Juneau is refilling fast six weeks after its Aug. 13 release pushed the Mendenhall River past major flood stage and forced evacuation advisories for roughly 1,900 residences. It has regained about 70 percent of the depth it lost. The National Weather Service Juneau office says a secondary release could come at any time, though none is forecast and no flood watch or warning is in effect.

A second release has come in each of the past two autumns. One ran Oct. 19 to 21, 2024, cresting at 10.77 feet, a moderate flood. Another ran Sept. 14 to 16, 2025, at 9.63 feet, a minor flood. A full release now would bring minor flood-stage impacts, the state assessed Sept. 24.

The basin peaked at 1,345.63 feet Aug. 11 and fell to 889.76 feet by Aug. 15. The weather service puts it at 1,210 feet as of Sept. 26, unchanged for three days. Its page, updated Sept. 21, says laser data is down because water levels are low. The same page also says laser and camera data show continued filling. USGS posted 1,183.95 feet Sept. 24 and nothing since, so the true level is unknown from these records. The agencies also differ on August peak flow, reporting 32,100 compared with 35,300 cubic feet per second.

The river was 2.2 feet Sunday morning, with 3.94 feet forecast Monday night. Flood stage is 9 feet, the point where water reaches Mendenhall Lake Campground. At 10.5 feet, the campground is evacuated. At 11 feet, some View Drive and Meander Way yards flood.

That August flood was the fourth straight major one and the smallest, cresting at 14.71 feet. The 2025 crest of 16.65 feet remains the highest of 70 crests recorded since 1966. Gov. Mike Dunleavy issued a state disaster declaration after Juneau and the Central Council of the Tlingit and Haida Indian Tribes of Alaska jointly requested assistance Aug. 12.

The State Emergency Operations Center was at Level 2 on Sept. 24. That day's report promised another update Sept. 25, which has not appeared, though the division publishes weekdays only and a missing Friday report has precedent. Juneau held a resident debrief Sept. 16, and its survey runs through Oct. 16. No responses are published yet, and no city notice mentions the refill or a possible release.