Suicide Basin’s water level drops temporarily, but ‘release is increasingly unlikely at this time,’ says NWS Juneau

Secondary releases have occurred in past years after major floods in August; weather service says water rising again Tuesday afternoon after drop during morning

A view of Suicide Basin when it was confirmed to be draining underneath the Mendenhall Glacier on Aug. 12, 2025. (Photo courtesy of Eran Hood)

By Mark Sabbatini

Juneau Independent

Update 3 p.m.: The National Weather Service Juneau, in a bulletin at about 2:25 p.m. Tuesday, stated Suicide Basin’s water level is "near steady to slightly rising."

"While the basin will continue to be monitored closely, a release is increasingly unlikely at this time," the bulletin notes.

Original story 11:30 a.m.: A drop in Suicide Basin’s water level indicates a possible release is occurring, but if so the basin’s water level is low enough that the Mendenhall River is not expected to reach the flood stage, according to National Weather Service Juneau officials.

A special weather statement issued at about 9:50 a.m. Tuesday notes: "The latest camera imagery/water level data from inside the basin showed a drop in water level. This could be an indication that a basin release has started."

"NWS hydrologists and meteorologists along with their partners are assessing and analyzing the information," the statement adds. "This statement will be updated within the next 24 hours so check back on this possible evolving situation."

Brian Bezenek, a NWS Juneau meteorologist, said in an interview at about 11 a.m. the basin’s water level has leveled off since the drop was observed Tuesday morning, so "this could have been easily one of the things (such as) an iceberg running underneath the sensor that we use to measure the height."

A graph shows the predicted level of the Mendenhall River if a full release from Suicide Basin were to occur on Tuesday, Sept. 15, 2026. (National Weather Service Juneau)

At 7 a.m. Tuesday the basin was at 1,140.8 feet and at 9 a.m. it was at 1,138 feet, according to weather service’s official monitoring website. When the basin released on Aug. 11, it was overtopping at a level of about 1,345 feet. The Mendenhall River crested on Aug. 13 at 14.7 feet, a rise of more than 10 feet from when the release began.

The Mendenhall River was at 2.7 feet as of 9:15 a.m. A hydrograph published at 10 a.m. shows a full basin release would result in a level just below the minor flood stage of nine feet. The moderate flood, or "action" stage, is 10 feet.

"Right now our best guess is that it would not reach flood stage," Bezenek said.

• Contact Mark Sabbatini at editor@juneauindependent.com or (907) 957-2306.