A resident of the Mendenhall Valley sits by sandbags loaded at an event held on July 26, 2025, by the City and Borough of Juneau and the Central Council of Tlingit and Haida Indian Tribes of Alaska. By 1 p.m. that day, more than 100 cars had checked in at the Dimond Park Field House, according to city officials. Each household was allowed to fill 75 sandbags. The event, one of several held by municipal and Tribe officials, was in anticipation of another glacial outburst flood. (Photo by Corrine Smith/Alaska Beacon)
A long-awaited glacial flood is hitting Alaska’s capital city.
On Tuesday morning, local officials sent warning messages to cellphones across the City and Borough of Juneau, alerting local residents that the Mendenhall Glacier’s ice-dammed lake has burst its barrier and is sending a torrent of water toward homes and businesses in the Mendenhall Valley.
“We are prepared for this situation. We’ve been preparing for this situation,” said Sabrina Grubitz, public safety manager for the Central Council of the Tlingit and Haida Indian Tribes of Alaska, and the commander of a unified local government task force responding to the flood.
The flood is expected to peak Wednesday afternoon at 16.6 feet, likely setting a record and surpassing a flood last year that damaged more than 290 homes.
With the U.S. Army Corps of Engineers stating that permanent flood barriers could be years off, local officials have installed semi-permanent HESCO walls in some neighborhoods to avert the worst flooding.
Those barriers have not yet been tested in an actual flood.
Local officials have asked residents in the affected area to voluntarily evacuate in case the barriers do not perform as intended.
During a briefing on Tuesday morning, Ryan O’Shaughnessy, director of emergency programs for the City and Borough of Juneau, gestured at maps showing the predicted inundation without the barriers.
“We strongly encourage everyone in the 17-foot inundation layer to evacuate their homes sometime today. There’s no need to rush out of neighborhoods, but we encourage folks to take a moment, take a deep breath, remember that they have a plan. This is something that we’ve been planning for as a community. Grab their go bag, let their family and friends know where they’re going, and then execute that,” he said.
Capital City Fire/Rescue Assistant Chief Sam Russell warned local residents to not stand on the flood barriers and for sightseers to stay away from the area.
Public radio and television station KTOO has set up several live video streams with instant information for people who want to keep an eye on the situation.
“I know everybody wants to see what’s going on, but we have cameras that are posted on the website, and you’ll be able to observe from there other things that are going on,” he said.
An evacuation shelter has been set up at nearby Floyd Dryden school, O’Shaughnessy said, and a non-emergency hotline has been set up for people who need information about shelter, transportation or other things. That number is 907-500-0890. Any road closures can be monitored at 511.alaska.gov.
As of Tuesday afternoon, much of the Mendenhall Glacier Recreation Area — Alaska’s most-visited tourist attraction — was closed to the public. The glacier’s visitor center remained open, but most trails, including the heavily trafficked Nugget Falls Trail, campground and West Glacier Trail, were closed.
On Monday, Gov. Mike Dunleavy issued a preemptive state disaster declaration “in response to an imminent threat of catastrophic flooding,” to support a coordinated interagency emergency response. “By issuing this declaration before the flood occurs, we can position state resources and personnel in advance to support local and tribal governments in their efforts to protect
lives, homes, and essential services,” Dunleavy said in a statement with the announcement. “Our goal is to act early to reduce impacts and preserve community safety.”
This week’s flood has been anticipated for months. Since 2011, the Mendenhall Glacier has caused floods each summer as Suicide Basin — a glacially locked lake — fills with meltwater and runoff, then bursts from its confines after the water overtops an icy dam.
As more ice melts amid global climate change, the flooding has grown worse. In 2023, the flood eroded the Mendenhall River’s banks, causing homes to collapse. In 2024, the flood was the worst yet.
After that experience, city and local officials mobilized to avoid a repeat, and they’ve been monitoring Suicide Basin closely.
This week’s flood was forecast well in advance, and residents were repeatedly warned ahead of time. On Monday, workers went door to door, distributing almost 900 warning flyers, “and there’s an additional 200 residents that are being contacted this morning directly,” O’Shaughnessy said.
Nicole Ferrin, warning coordination meteorologist with the National Weather Service forecast office in Juneau, said officials expect the Mendenhall River “to continue to rise through the next 24 hours, with a crest sometime Wednesday afternoon, around 16.6 feet. But that plus or minus half a foot, so a range of 16.3 to 16.8 is probably more fair.”
That expectation is based on prior experience and computer modeling, and it could be altered by tomorrow morning, she said.
“I should note that we’re already at minor flood stage,” she said Tuesday morning, “and this will be a new record based on all of the information that we have.”
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