Malcolm Herstand (DGGS) in Barry Arm
Cyrus Reed and John Lyons (USGS) servicing Barry Arm hydrometeorological instruments
Seismic Station BAE with recently repaired camera (Karasozen, AEC)
Fresh batteries in seismic station BAE (Karasozen, AEC)
Sean Lahusen (USGS) near Maynard Mountain.
Bill Schulz (USGS) at Yale Arm.
An ongoing landslide and landslide-generated tsunami threat exists in Barry Arm, northwestern Prince William Sound, Alaska. The landslide is stable or exhibiting slow rates of deformation (<50 mm/d). Localized areas of higher velocities may be evident, but movement is largely surficial. While potential failure of these areas may result in a localized tsunami, failure is unlikely to represent a region-wide tsunami threat. Partial or catastrophic rapid failure is unlikely without external forcing, such as that associated with a strong regional earthquake. "Small" but infrequent rockfalls and shallow landslides may be commonly observed.
Mariners should remain vigilant when in the vicinity of Barry Arm or nearby waters and be prepared to depart the area if any unusual rockfall activity is seen or heard, or if unusual waves, currents, or tides are observed.
DGGS organized a multi-agency Alaska Natural Hazards Workshop September 1-2, including a half-day workshop on August 31 focused on Barry Arm Landslide. This workshop provided a platform for state and federal scientists, emergency managers, and stakeholders at the tribal, local, state, and federal levels to explore how we can be more prepared to respond to disastrous natural events. Over 30 attendees participated in the Barry Arm half-day workshop, which used a tabletop exercise and panel discussions to walk through what a landslide-generated tsunami response would look like in the first 24 hours, from initial warning through evacuation, search and rescue, and public communication. Key outcomes included a clearer picture of current response capabilities, identification of coordination gaps to address going forward, and stronger relationships between the many agencies who would need to work together during such an event.
The USGS, DGGS, NTWC, and AEC have all been busy at Barry Arm with boat and helicopter-supported fieldwork in August and September. Accomplishments include a new lidar collection covering the Barry Arm landslide, removing a temporary seismic array, moving an infrasound array to a new location north of seismic station BAE, replacing a modem and router at the Mt. Doran repeater site, repairing telemetry at BAE Node 4, resetting the precipitation gauge, repairing seismic station cameras, replacing batteries at water level sensors and seismic stations, and re-installing the Whittier dock tide gauge.
Elsewhere in Alaska, USGS scientists Brian Collins, Autumn Helfrich, and Callie Price (Geology, Minerals, Energy, and Geophysics Science Center, Moffett Field, California) and Charlie Miles (Geologic Hazards Science Center, Golden Colorado) continued their field campaign using a portable ground-based radar system on Maynard Mountain. The data from their 10-day repeat survey in September 2026 will be compared with their survey of the same location in 2025 to better understand slow landslide deformation patterns at this location.
USGS scientists Nikita Avdievitch (Alaska Volcano Observatory, Anchorage Alaska) and Sean Lahusen (Geology, Minerals, Energy, and Geophysics Science Center, Moffett Field, California) collected structural field data at the base of Maynard Mountain and in the 1964 rock-avalanche deposit that failed off the landslide. The lack of a favorable aviation weather window in early September prohibited planned work at higher elevation or other Prince William Sound sites and will take place at a future date.
USGS scientists Bill Schulz (Geologic Hazards Science Center, Golden Colorado) and Dennis Staley (Alaska Volcano Observatory, Anchorage Alaska) conducted reconnaissance at landslides in Columbia Bay, Yale Arm, and Portage Valley to better understand geologic structures and lithology as they relate to the geotechnical properties of rock that are important for landslide behavior and susceptibility; namely material strength and resistance to shearing forces. The observations collected September 22 – 24 2026 will aid in the interpretation and implications of ring shear testing that Bill is conducting in partnership with scientists at the University of Kyoto, Japan.
| Monitoring Method | Agency | Operational Status | Notes |
|---|---|---|---|
| Water Level | NTWC | Online | |
| Seismic - BAE | AEC | Online | |
| Seismic - BAT | AEC | Online | |
| Infrasound - BAEI | USGS | Online | |
| Ground-Based Radar | USGS | Online | |
| Deformation camera | USGS | Online | |
| Satellite InSAR and imagery | USGS | Online | |
| Hydrometeorology - BAE | DGGS | Online | |
| Hydrometeorology - BAW | DGGS | Offline | Decomissioned |
| Hydrometeorology - Mt Doran | DGGS | Online |
(Last updated February 2, 2024)
The Barry Arm landslide is a large (~500 M m3 or 650 M yd3) landslide located in the northwestern corner of Prince William Sound, Alaska. Rapid failure of the landslide has the potential to create a tsunami that results in life-threatening waves and currents in Barry Arm, Harriman Fjord, Port Wells and adjacent fjords. The existence of the landslide is evident in photographs dating back to at least 1935, with possible evidence of the landslide in photographs dating to 1913.
Throughout the observational record, the Barry Arm landslide has experienced slow movement punctuated by episodes of acceleration. While slow downslope movement is both common and expected, rapid increases in the rate of movement may be a possible precursor to catastrophic failure. As such, observations and hazard messages are often centered around trends in the observed rates of downslope movement at Barry Arm, as measured by ground-based, aerial, and satellite surveillance methods.
The Barry Arm landslide is being monitored by a multiagency team of scientists from the U.S. Geological Survey (USGS), National Tsunami Warning Center (NTWC), Alaska Division of Geological & Geophysical Surveys (DGGS), and the University of Alaska Fairbanks Alaska Earthquake Center (AEC). For more information on monitoring activities, equipment and data availability, please visit https://landslides.usgs.gov/storymap/barry-arm/.
(Last updated February 2, 2024)
Scientists at USGS, DGGS, AEC, and NTWC will continue to make every effort to minimize outage of this critical network of sensors. The Alaska environment and its inhabitants can wreak havoc on our sites: strong winds can damage sensors, power components, and antenna; deep snow can bury instruments and solar panels and makes it difficult to access (and even find) sites, rain can work its way into sensitive electronics, and our four-legged neighbors, such as bear, deer, and goats, have a taste for our wiring and enclosures. While we have made our best effort to harden the sensors, power systems, and telemetry for continuous operation of the equipment and to resist weather and animals, it is necessary to have reasonable expectations given the difficulties of working in this harsh environment. Reasonable expectations include:
This message will be updated on November 6, 2026, or earlier if the threat level changes. For more information, please see our Barry Arm Summary Information & FAQ page.
