Landslides have killed at least a dozen people in Southeast Alaska in recent years.
That prompted Aaron Jacobs, a hydrologist at the National Weather Service in Juneau, and his colleague to answer a major question people in the region have been asking: “Are we seeing more landslides across Southeast?”
A couple of years ago, scientists weren’t sure. Now, Jacobs says the answer is yes.
According to the study, published in the journal Landslides in November, news outlets reported 281 destructive landslides between 1883 and 2025 in Alaska. Jacobs said they decided to use news reports as the data source because if a landslide affected people or infrastructure, it probably made the news.
They found the number of reported landslides started to increase in the 1980s and has skyrocketed in recent decades.
Fewer than 10 damaging landslides were reported per decade before 1980. From the 1980s to the 2010s, they found a 295% increase across the state. In the 2010s, 84 damaging landslides were reported. In just the first half of the 2020s, 76 landslides have made the news.
“A big thing that stuck out was the precipitation-driven or triggering events that were increasing within the last 20 years,” Jacobs said.
The four fatal landslides that hit Southeast in recent years — Sitka in 2015, Haines in 2020, Wrangell in 2023 and Ketchikan in 2024 — were all triggered by heavy rain or rapid snowmelt.
In the paper, the scientists drew a connection between rising average annual air temperatures — between 1.2 and 3.4 degrees Celsius — and a 3% to 27% increase in precipitation across Alaska over the past half-century.
“It’s all connected,” Jacobs said.
It’s a result of climate change. As the globe heats up, more intense atmospheric rivers are slamming Southeast because warmer air can hold more moisture. These downpours cause steep slopes to crumble.
Climate change is also expected to increase the frequency and intensity of storms that dump rain on top of snow. When the rain melts the snow, it rapidly saturates hillsides and can make landslides more likely. Additional research, published Wednesday by Jacobs and others, found that this phenomenon triggered the 2023 Wrangell landslide.
Earlier this month, Jacobs and his colleagues posted a manuscript of a scientific paper addressing these rain-on-snow events that hasn’t been peer-reviewed yet. They used a high-precision weather forecasting model to assess atmospheric rivers in Southeast within the last handful of decades and project how they could change in the near future.
The researchers found that rain-on-snow events coincided with 8% of landslides assessed between 1981 and 2019, including some that were large and widespread. They predict that rain-on-snow events will happen more often and involve an increase in extreme rainfall and snowmelt between 2031 and 2060 as the atmosphere continues to heat up.
How people use the land also plays a role in where landslides occur and how they affect people. On Prince of Wales Island, scientists have mapped nearly 800 landslides. The island is crisscrossed by hundreds of miles of logging roads.
“The writing is on the mountain,” said Quinn Aboudara, natural resources manager for the Shaan Seet tribal corporation in Craig.
He said he’s noticed that landslides are more prevalent in logged patches and where roads cut across steep slopes. When he was growing up in Port St. Nicholas Bay, he said landslides weren’t as frequent and more snow fell in the winter. In recent years, it mostly rains.
“Now we treat the rainy seasons as landslide season,” he said.
Shaan Seet is piecing together a road and culvert inventory to identify problematic areas. During a deluge, Aboudara said some old culverts meant to funnel water under roads clog or just aren’t big enough to handle the runoff. He said that causes water pressure to build up in the hillside and can lead to landslides.
“We’re looking to replace those with actual bridge works instead of culverts,” he said.
At the Sitka Sound Science Center, Luka Silva is working on other measures to reduce risk. He manages the Ḵutí Geohazards Project, which works with Southeast communities to address gaps in landslide science and public safety.
“Because no one wants to lose their neighbor or their home or their friends or loved ones in a landslide, and we have steps that we can take to make that less of a possibility,” Silva said.
The center developed an early warning system for Sitka that Silva said other communities are using as a model. Scientists are studying soil thresholds to someday forecast landslides. Many communities are working on or already have landslide hazard maps.
But some municipalities have struggled to take action. After residents in Juneau pushed back against updated landslide hazard maps, the Juneau Assembly declined to adopt them and rolled back development restrictions in landslide paths. Nearly identical stories played out in Sitka and Haines. It’s because homeowners don’t want to see their property values tank and insurance premiums rise.
Silva urges people to keep the bigger picture in sight.
“We know what we know about how our landscape is going to change even further, and how our landslides are going to be more and more impactful and frequent,” he said. “What are we going to do about that? And what are we going to do to make people safer?”