Record Juneau Flood, Barriers Hold; Mendenhall Glacier Shut

Published on Aug 13, 2025, 6:20 pm CDT

7 min read

Juneau's glacial outburst flood peaked at record levels on August 13, yet the city's new temporary levee system largely contained the worst damage. The U.S. Forest Service has closed the entire Mendenhall Glacier Recreation Area until further notice, and city officials report damage to a key bridge that serves the valley. Cruise calls are continuing, but many glacier excursions are paused or rerouted. Travelers should expect rolling trail, road, and tour closures as assessments continue, and build flexibility into late-summer Alaska plans. See our earlier alert, Alaska Braces as Mendenhall Glacier Flood Begins.

Key Points

Why it matters: Record crest, closures at Mendenhall Glacier, itinerary adjustments likely.
Travel impact: Trails, roads, and select tours closed, cruises still calling, excursions modified.
What's next: Multi-day safety assessments, phased reopenings, and tour redeployments as waters recede.
New flood barriers protected hundreds of homes, minor seepage and debris damage reported.
Back Loop Bridge is closed for repairs, plan extra time for local transport and staging.

Snapshot

The Mendenhall River crested at about 16.65 feet on August 13, surpassing last year's record. Temporary HESCO barriers along roughly two miles of riverbank protected many neighborhoods, with localized seepage and debris impacts. The U.S. Forest Service closed all of the Mendenhall Glacier Recreation Area, including Nugget Falls Trail, Photo Point, Dredge Lakes, and Glacier Spur Road, pending inspections. Back Loop Bridge on Mendenhall Loop Road is closed for abutment repairs. Cruise calls are proceeding in Juneau, and downtown attractions remain available, but glacier-area tours are paused or reworked. Flyers into Juneau International Airport (JNU) should expect changing local detours, plus an FAA temporary flight restriction for response aircraft.

Background

Juneau's summer floods originate in Suicide Basin, a side basin near Mendenhall Glacier that periodically releases impounded melt and rainwater. Since 2011, these glacial outburst floods have recurred, with major events in 2023 and 2024. Anticipating another high-water year, the City and Borough of Juneau, with state and federal partners, installed a temporary levee of HESCO barriers to shield riverfront neighborhoods. The system was designed to defend hundreds of properties up to about an eighteen-foot lake level, and it was tested by heavy rains and a large basin release this week. Authorities issued evacuation advisories for unprotected areas, staged shelters, and warned residents to avoid flood zones. The Forest Service moved to close popular trails and viewing points before the crest, then extended closures after the peak to allow for damage checks and debris clearing. Tour operators began canceling or shifting glacier-area excursions.

Latest Developments

Mendenhall Glacier closures and access

The Forest Service has closed the entire Mendenhall Glacier Recreation Area until further notice. That includes the Visitor Center building and grounds, Nugget Falls Trail, Photo Point, Dredge Lakes, West Glacier, and Glacier Spur Road. Travel Juneau reports power is off at the Visitor Center, with on-site services unavailable, and warns that entering the closure zone may carry fines. Rangers indicated it could take several days to assess conditions once river levels drop into minor flood stage. Expect a phased reopening by unit and trail, not all at once. If you are booked on a glacier-area tour this week, contact your operator for updates, and consider alternative plans downtown or on the water. Our continuing coverage, Alaska Braces as Mendenhall Glacier Flood Begins, explains the triggers and the city's response steps.

Transport, bridges, and safety for touring days

Alaska DOT reported erosion damage at the Back Loop Bridge abutment on Mendenhall Loop Road, prompting a full closure to vehicles, cyclists, and pedestrians. Detours add time to staging and pick-ups for local tours, ride shares, and independent travelers. Officials emphasize staying out of the floodplain and off closed roads until engineers complete inspections. A temporary flight restriction is active over parts of the valley to support geohazard monitoring and response flights, which can affect sightseeing helicopters during certain windows. River levels are falling from the Wednesday morning crest, yet remain in flood stage until hydrologists declare an all-clear. Expect rolling utility work as crews restore power in affected neighborhoods and clear debris from access points that support popular tour routes.

Cruise calls continue, but glacier excursions are fluid

Juneau's cruise schedule shows multiple ships alongside on August 13 and 14, with port operations continuing. The flood zone sits inland from the docks, so ship arrivals proceed while Mendenhall-centric tours face the bulk of disruption. Operators are swapping in alternatives like whale watching, Tracy Arm fjord cruises, downtown museums, food tours, and the Mount Roberts Tramway when conditions allow. Some lines may adjust call times to accommodate redeployed shore-excursion inventory and traffic detours. If your sailing lists Mendenhall Glacier or Nugget Falls, monitor your cruise app and email for replacement options or credits. Independent travelers should build a Plan B and Plan C for Thursday and Friday, then reassess as official inspections finish.

Analysis

For travelers, the headline is reassurance with caveats. The barrier system did its job, limiting widespread residential damage and keeping core tourism infrastructure functioning. That allowed ships to keep calling, hotels to host guests, and tour vendors to pivot rather than shut down. The caveat is that Mendenhall Glacier, Southeast Alaska's single most in-demand excursion, is offline until the Forest Service can inspect trails, bridges, and shorelines. Safety is non-negotiable when flood debris, unstable banks, and downed trees are present. Expect several days of rolling closures, with different units reopening on different timelines.

Late summer in Southeast Alaska is now a high-variance period for glacial outburst floods. The basin's behavior is seasonal, but the exact release timing can shift by days, and rainfall can amplify impacts. Cruise lines and operators have learned to flex quickly, swapping glacier stops for fjord cruises, wildlife trips, and culture-forward tours. Smart travelers mirror that approach. Book refundable excursions, favor vendors with easy rebooking policies, and schedule glacier-area plans earlier in the day, when operations often resume first. If Mendenhall remains closed on your call day, route to whale watching, Tracy Arm, or food and art experiences downtown, then revisit the glacier on a future trip. Alaska rewards flexibility, and the quality of alternatives remains high even when a marquee site pauses.

Final Thoughts

Juneau's record crest and successful levee test are a turning point for residents and visitors. The city bought time, protected neighborhoods, and kept most travel moving, even as Mendenhall Glacier closed for safety. Over the next several days, watch for staggered reopenings, tour redeployments, and updated guidance from rangers and the city. If you are sailing this week, keep your schedule flexible, treat glacier access as a bonus, and lean into strong alternatives on land and sea. You will still find Southeast Alaska's wildlife, fjords, and culture on full display, even while crews work to reopen Mendenhall Glacier.