Juneau officials review response to glacial lake outburst; Army Corps study, longer-term work next

City and Borough of Juneau officials on Aug. 18 updated the Assembly on their response to a 2025 glacial lake outburst flood, saying a unified command led by tribal and city emergency staff coordinated dozens of partner agencies to protect neighborhoods but that seepage and a localized HESCO barrier failure caused property impacts and exposed remaining vulnerabilities.

The unified command, hosted at the Tlingit and Haida Public Safety Facility, included about 60 responders from the city and borough, tribal partners, the Alaska Department of Transportation and other agencies, officials said. "Tlingit and Haida was honored to host, at our Public Safety Building. That meant around 60 different responders," said Sabrina Grubitz, the Tlingit and Haida public safety manager, who served as an incident commander.

Why it matters: officials said the temporary HESCO barriers prevented a wider disaster but are not a long-term fix. City staff and the Army Corps of Engineers are pursuing an engineering and funding path for a Phase 2 project and an eventual enduring solution; both will require more data, hydrologic modeling and federal funding. The assembly heard preliminary cost and damage estimates and was told more months of work are needed before recommended construction or financing decisions are ready.

Officials said the river crest during this event reached about 16.65 feet. Incident commanders and staff described the HESCO barriers as holding back most flow from the Mendenhall River but allowing seepage in places and experiencing isolated failures. "It cannot be overstated how integral the collaboration was to our response to this year's glacial lake outburst flooding," said Ryan O'Shaughnessy, an incident commander. He and other speakers described a DOT drone mission that used three drones and produced roughly 18 hours of footage streamed to the emergency operations center.

Incident briefings included a damage assessment dashboard that categorized structures under FEMA-like metrics: 16 homes were listed as "affected" (water in a garage or crawl space), 25 homes as sustaining "minor" damage (removal of some building materials typical but limited damage to mechanical systems) and six homes as sustaining "major" damage. Officials said several unverified reports on the dashboard were expected to fall to lower damage categories after follow-up inspections. City staff said five of the six homes listed as major damage were on View Drive and were not protected by HESCO barriers.

The incident commanders described a single, full HESCO failure caused when a falling tree removed a roughly 15-foot segment of barriers near Diamond Park. "You can see this person runs away as they should. Eight seconds later, the HESCO barriers are destroyed," Grubitz said, describing video evidence. Officials said that in this case timing and location prevented the failure from producing greater property loss.

City Manager Kester gave a preliminary estimate of damage and project impacts: "Up up to a million was our preliminary assessment. Don't have that confirmed, but really wanna underscore that. It is not insignificant." That figure referred to the existing HESCO project repairs, bank stabilization and related immediate recovery; staff said additional costs for Phase 2 design and construction would be much larger.

Officials described the Army Corps' role and the next technical steps. The Corps is conducting a technical study to collect data that will feed an engineering study; the engineering study would identify a preferred alternative the Corps can present to Congress for funding. Brigadier General Getz, the Corps' Pacific Division civil works leader, and U.S. Sen. Dan Sullivan attended recent briefings and have told local leaders they will help pursue federal engineering funding and congressional support. Officials said the Army Corps' engineering step will require funding and that, under the Corps' process, some studies expect a local match (staff noted a 50% local-match requirement for parts of the engineering work as the Corps currently describes it).

Assembly members asked about homeowners on View Drive, where several properties are outside the HESCO footprint. Staff said the Natural Resources Conservation Service (NRCS) has conducted a preliminary assessment for a possible buyout program; NRCS buyouts typically require a 25% local match and include demolition and returning the property to parkland, staff said.

On infrastructure, staff reported damage to some trails and road segments and said the Bridge on Back Loop (Montana Creek crossing) remains closed while DOT completes assessment and design; staff said DOT has no firm timeline to reopen the bridge. Officials also noted ongoing debris removal and directed residents with remaining debris to use the flood response hotline to schedule pickups.

What comes next: staff said they will continue damage assessments, coordinate contractor and Corps work on immediate repairs and develop Phase 2 options for the assembly. The manager asked for months of hydrologic modeling and engineering work before asking the Assembly to make major funding commitments. "It's gonna take us months to be able to get you the information that you need to make another round of really, impactful decisions about what to spend money on and how to pay for it," Manager Kester said.

The Assembly did not take formal votes on design or funding during the Aug. 18 meeting. Staff asked the public to remain off HESCO barriers during high water events and reiterated that the barriers are a temporary protective measure while longer-term options are developed.

A flood-response joint information center and coordinated public messaging were credited with improving communication to residents during the emergency. Officials said lessons learned will inform improvements to barrier design, maintenance and communications ahead of next year's runoff season.