Suicide Basin release to push Mendenhall Lake near 10 feet Friday

A second release of water from Suicide Basin is expected to send flooding to the Mendenhall Glacier Visitor Center, West Glacier Trail, Nugget Falls Trail and Mendenhall Campground Road Friday afternoon. The National Weather Service in Juneau forecasts Mendenhall Lake will crest between 9.8 and 10.3 feet sometime between 2 and 6 pm.

A Flood Warning is in effect until 7:45 a.m. Saturday for Mendenhall Lake and River near the glacier recreation area, View Drive and below the Back Loop bridge. Ten feet is moderate flood stage at the lake gauge. At that level, the warning says, areas along View Drive will start to flood, with minor flooding of yards; Skaters Cabin Road could take up to 1.5 feet of water; and pedestrian pathways beneath Brotherhood Bridge and the trail system on the river's west side close. From 7.7 feet, bank erosion along the river can bring dangerous tree fall and make floating the river more hazardous. The warning also cautions that cold water raises the threat of hypothermia.

A forecaster from the Juneau office gave the forecast Thursday in a short YouTube livestream. "This is not uncommon. We've seen secondary releases before," the forecaster said.

The lake is expected to pass 9 feet, its flood stage, near 10 a.m. Friday. "I think we'll go above 9 feet sometime near 10 AM Friday, and then, that's when the river really starts to change," the forecaster said.

The forecast assumes the full basin drains. The forecaster said a partial release is possible and is common with secondary releases. For now the office will keep messaging a full release, with a crest near 10 feet.

"The biggest impact that we're keying in on is going to be for the Glacier Visitor Center, the Mendenhall, like West Glacier Trail," the forecaster said. The forecaster said Mendenhall Campground Road could see about 3 feet of water.

This year's main release crested at 14.7 feet on Aug. 13, after about 1,900 residences were advised to evacuate. In 2024, a secondary release ran Oct. 19 through 21 and crested at 10.77 feet, according to the NWS Suicide Basin page.

The office plans to update its Suicide Basin monitoring page every hour through Thursday and into Friday. That page is posted at weather.gov/ajk/suicidebasin. Updates will also go out on social media, and the forecaster said another livestream is possible. The Juneau office takes calls at 907-790-6824.