A violent landslide has raced down a forested hillside in Ketchikan, Alaska, killing one person and injuring three.
“In my 65 years in Ketchikan, I have never seen a slide of this magnitude,” Dave Kiffer, the town’s mayor, said in a statement. “There is clearly a regionwide issue that we need to try to understand with the support of our state geologist.”
The disaster, which struck around 4:15 p.m. on Sunday, followed a period of unusually heavy rain known as an atmospheric river. Scientists said that intensifying rainfall, driven by climate change, could increase the risk of landslides in the area of Southeast Alaska that includes Ketchikan.
“There’s no single factor that seems to underline each of these events apart from a lot of moisture,” said Josh Roering, professor of earth sciences at the University of Oregon.
The landslide cut through a hillside and crashed into several homes at the top of town, a hilly fishing community of about 14,000 where cruise ships often dock. Four ships had been expected there on Monday.
Three people were transported to the Ketchikan Medical Center. One was treated and discharged and two were admitted, city officials said. The city hasn’t made public details about the person who died. An emergency shelter was opened at the local high school where a dozen people were staying as of Monday morning.
The town has two main roads and one of them was hit by the slide, according to Danielle Tessen, a spokeswoman for the Alaska Department of Transportation and Public Facilities. An evacuation order has closed several smaller streets below the slide as state geologists work to determine the risk of more landslides.
Landslides can be triggered by heavy, long periods of rain or short, intense bursts of precipitation, particularly when they occur in narrow valleys or on steep ridgelines. Along with increases in rainfall, these disasters are also connected to rapid snow melt and retreating glaciers, which are also hallmarks of a warming climate.
Globally, this year has been “exceptional in terms of fatal landslides,” according to Dave Petley, author of The Landslide Blog and vice-chancellor of the University of Hull in England. At least 430 fatal landslides have led to more than 3,600 deaths in 2024. Dr. Petley has said possible causes could include high intensity rainstorms and rising global surface temperatures.
But in Southeast Alaska, perhaps the biggest factors have been atmospheric rivers, or long narrow bands of intense water vapor. While these events are common in the region, lasting for up to two weeks of every month, experts say the moisture they carry is expected to increase under climate change.
Before the landslide this past weekend there was “an abnormally strong atmospheric river for this time of year,” said Deanna Nash, a postdoctoral researcher at the Scripps Institute of Oceanography in San Diego. It produced two to four inches of rain and strong winds, according to Aaron Jacobs, senior service hydrologist and meteorologist for the National Weather Service in Juneau, Alaska.
“Pretty much anywhere in southeast Alaska that has steep hillsides associated with it is subject to a potential landslide,” said Ron Heintz, senior researcher at the Sitka Sound Science Center, a nonprofit research organization in Alaska. The southeastern part of the state is dominated by fjords and loose soils left behind when glaciers receded some 12,000 years ago.
There have been numerous deadly landslides in the region over the past decade.
In 2015, a landslide killed three people in Sitka, north of Ketchikan. Five years later, a landslide killed two in Haines, a town in the state’s southeast, and in November a landslide killed six people in Wrangell. A state report showed that the Wrangell landslide had been caused by pounding rain over the six-hour period preceding the disaster.
“It’s a pretty tough string of events this region has been dealing with,” Dr. Roering said. He is part of a five-year National Science Foundation study that could lead to the creation of landslide hazard maps and early warning systems for six towns and tribal communities.
Right now, Sitka is the only town in the region to have a landslide warning system, which gives residents real-time forecasts of landslide risk via a phone app.
Immediately after the 2015 Sitka landslide, the community adopted ordinances that limited development in risky areas, but those have since been removed, Dr. Heintz said, because residents felt they were too restrictive.
“In Sitka, like in every community we’ve encountered, everyone wants to see landslide run-out maps,” said, referring to maps that show the possible routes of future landslides. “But once they see where their property is in the run-out map, then they want the map thrown away,” Dr. Heintz said. “It’s a serious problem trying to figure out what to do.”
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