From the Southeast rainforest to the Arctic tundra, warming conditions are creating a variety of Alaska landslide hazards, some of them posing extreme hazards to human safety and others creating expensive problems for important infrastructure.
Just how many hazardous sites are out there? Bretwood “Hig” Higman, a geologist based in the Kenai Peninsula town of Seldovia, has done a basic inventory.
From 2012 to early this year, there have been more than 1,000 slow-moving slides of different varieties, with triggers that include receding glaciers, thawing permafrost, extreme weather or combinations of those factors, according to his calculations.
In a state where people contend with earthquakes, floods, wildfires and erupting volcanoes, it may be difficult to add another type of natural disaster to the public’s list of worries, Higman said. But elevating landslide awareness and preparedness is necessary as events increase, he said.
“It is vastly more risky than most things we deal with,” said Higman, a partner in an Alaska landslide science program created by the Massachusetts-based Woodwell Climate Research Center.
The lesson has been learned in Southeast Alaska, where catastrophic slope failures triggered by extreme rains have proved deadly. Since 2015, 12 people have been killed by landslides in Sitka, Haines, Wrangell and Ketchikan, including a family of five in Wrangell in November 2023.
In Southeast, steep mountains that were created through tectonic processes rise from the water’s edge, and rain is frequent. It is naturally susceptible to landslides.
“One of the primary processes that sculps the landscape in Southeast Alaska is landslides and glaciers and rivers,” said Dennis Staley, a U.S. Geological Survey scientist and Alaska landslide program leader. “When you combine rapid uplift with steep slopes with junky rock and lots of rainfall, you have all of the key ingredients for landslides.”
Southeast Alaska landslides are classified as shallow slides because they involve the soil, trees and other materials atop the bedrock rather than the rock itself. Those slides are numerous; the USGS recorded 162 news-reported slides in Southeast from 1990 to 2024. They are longstanding threats. A 1936 landslide in Juneau, for example, killed 15 people.
Now climate change is compounding the threat by creating more extreme rainfall events, driven by atmospheric rivers, as well as bringing more winter rain that, in other years, would be snowfall.
That means efforts to monitor landslide risks extend not just to topography studies but also the details about precipitation. Whether it is rain or snow — or rain-on-snow — has implications for slope stability, and the multiagency team studying landslide risks in Southeast has developed a prototype monitoring station to record precise qualities of the precipitation, as well as wind and temperature.
Beyond federal and state agencies’ work and that of university organizations like the Alaska Earthquake Center at the University of Alaska Fairbanks, there is focused work by tribal governments and community organizations.
The Sitka Sound Science Center, previously known for its fisheries and ocean science work, now has one of the most well-developed landslide programs. The center’s landslide program was launched in 2015, after a slide there killed three. The center now maintains a local landslide hazards dashboard, and it participates in and coordinates a variety of research projects and educational programs.
One is the Kutí project, a partnership with the Central Council of the Tlingit & Haida Indian Tribes of Alaska and other tribal partners. Named for the Tlingit word meaning “weather,” the program is funded by a National Science Foundation grant awarded in 2022. The purpose is development of a more regional Southeast Alaska monitoring, warning and educational system.
The Sitka center’s work has been hampered by Trump administration budget cuts and policies. A landslide conference that the center was set to host last spring was canceled because Trump administration policies prevented federal partners from attending.
Farther north, slopes are shifting and creeping as permafrost thaws, creating hazards for infrastructure. The best-known case may be in Interior Alaska at Denali National Park and Preserve, where one of the more than 140 detected landslides along the park’s sole road interfered with travel.
That slide, at a site called Pretty Rocks at the midpoint of the 92-mile road, had been ongoing for years, creating maintenance headaches for park staffers trying to keep the road open. In 2021, it finally made the road impassable.
A project is underway to create a bridge over the slide area, but it is proving more complicated than originally envisioned. Early on, it was estimated to cost a bit under $100 million and expected to be completed by the 2025 tourist season. Since then, the completion date has been pushed back, with full road access expected to resume in 2027.
The cost is now estimated at $150 million, a figure that does not include potential work at other landslide sites along the park’s road.
Nationwide, the National Landslide Preparedness Act signed into law in 2021 has provided a big boost for landslide monitoring. Through that act, Congress in 2021 appropriated $4 million specifically to landslide hazards in Alaska’s Prince William Sound.
But the law, which authorized federal funding for landslide programs, expired in 2024.
Legislation is pending in Congress to reauthorize it, with sponsors from Alaska and Washington, states with deadly slides in recent years. Without reauthorization, prospects for future funding are clouded.
The Trump administration’s proposed budget for the coming fiscal year would cut funding for USGS natural hazards work — which includes landslide hazards — by about a quarter, from $203 million to $157 million, according to a Congressional Research Service report.
As with the canceled Sitka conference, Trump administration policy interrupted landslide work last spring in Prince William Sound. Massive federal staff layoffs and spending freezes prevented some planned maintenance work at the Barry Arm landslide site.
The Alaska Beacon is an independent, donor-funded news organization. Alaskabeacon.com.
