Juneau’s Suicide Basin: Flood warning issued

The data is not clear yet, but anecdotally it appears the water-and-ice basin that fills alongside the Mendenhall Glacier started releasing again late Friday night or early Saturday. The National Weather Service has issued a flood warning for parts of the Mendenhall Valley.

Juneau residents report that Fritz Cove near Gastineau Channel looked like chocolate milk, an indication that Suicide Basin had another outburst of water, known as a “Jökulhlaups,” the Icelandic word for glacial flood.

On Aug. 6, a major outburst of the basin led to record flooding in the Mendenhall Valley, where nearly 300 homes were impacted by flood waters, some severely.

The National Weather Service said that as of Saturday at 9:30 a.m., Mendenhall Lake was at 4.47 feet and continuing to rise. On Friday afternoon, the Weather Service said, Suicide Basin had lost 2.6 feet of measurable depth. That water flows in to Mendenhall River and makes its way to Fritz Cove and Gastineau Channel/Lynn Canal.

The camera and laser pool elevation gauge has been unhelpful due to snowy weather impacting the reporting of data. The last image available of Suicide Basin, shown above, is from Oct. 4, and shows the level of the ice-and-water level rising to nearly what it was when it caused catastrophic damage in August.

The Weather Service now says that the Mendenhall River could crest as high as 11.5 feet between 1-7 a.m. Monday. The last flood was nearly 16 feet.

At 9 feet flood stage, Skater’s Cabin will be under water. At 11 feet, View Drive will be flooded and impassible, and there will be some significant flooding of homes in the area. The Back Loop Bridge may see bank erosion along Meander Way, where homeowners may see flooding in their backyards. Portions of the Dredge Lake Trail will also be impassible.

On Monday, the Juneau Assembly will meet to discuss options. One option being considered is to authorize the purchase of oversized sand containers known as Hesco Flood Barriers, which would be placed along the river banks.That is a temporary solution and may only redirect flooding elsewhere if not done properly.

The Assembly meeting, which begins at 7 p.m., has this new item on the agenda:

“Emergency Resolution 3076 An Emergency Appropriation Resolution Appropriating up to $2,000,000 for Flood Levee Barriers; Funding Provided by Restricted Budget Reserves. This emergency resolution would appropriate $2,000,000 from the Restricted Budget Reserve for the installation of flood levee barriers. In response to glacial lake outburst flooding caused by the sudden release of water from Suicide Basin, the Assembly adopted Ordinance 2024-34 on October 3, 2024, entering the CBJ into a cooperative agreement with the Army Corps of Engineers for advanced flood mitigation efforts. This funding would contribute toward the first phase of installation of HESCO barriers along approximately four miles of the Mendenhall River to aid in the mitigation of future glacial outburst floods. Funding for this request is needed as soon as possible to authorize CBJ to incur expenses associated with this work in order to give the community the best chance at having this work complete before the next glacial lake outburst flood. For this reason, this is an emergency resolution. The City Manager recommends the Assembly adopt this emergency resolution.”

It appears the action by the Assembly may come too late for some homes, however, if water is already rising.

Others in the community have suggested longer-term solutions need to be considered, such as building an earth-filled levy around Mendenhall Lake itself, to better control and slow the release of water into the river.

That’s a solution that would require cooperation between the Forest Service, U.S. Army Corps of Engineers, and the City and Borough of Juneau. But as of now, the various agencies appear paralyzed as flood after flood begin to destroy the homes of people living in the Mendenhall Valley.

Unfortunately, there are few other places to build homes in Juneau, since the choices are mainly the landslide-prone mountainsides or the valley carved out by the Mendenhall Glacier. The U.S. Forest Service owns much of the land that could be used for housing, but is simply held onto by the federal government.

Some estimates say that the taxable property in the Valley makes up 20% or more of the City and Borough of Juneau’s taxable base. Hundreds of homes, however, may lose value quickly in part due to government inaction. There are more than $1 billion in assessed properties in that area of the community.

Release of water from Suicide Basin has gone on for years, but has recently become more dangerous and damaging. A major release in 2023 sent a couple of riverfront homes into the river, and then in August of 2024, the damage was extensive and, for some people, permanent.

As for the current situation in Suicide Basin, the Weather Service says, “There is greater uncertainty in crest timing due to cold temperatures and this being an unusually late season event.” On top of that, the camera isn’t working that shows the level of the basin, the days are getting shorter, and the weather has featured low clouds for days, further obstructing visual observation.