This story originally appeared in High Country News and is part of the Climate Desk collaboration

Nestled against glacier-capped mountains, the Begich Towers tower over Whittier, Alaska. More than 80% of the small town’s residents live in Cold War-era barracks at this former secret military port, including the port swarms with traffic every summer: barnacle encrusted fishing boats, tourist ships, sailboats, superyachts and cruiser monstrosities This summer, coronavirus travel restrictions put a damper on tourism in the generally bustling port Then came the warnings a potentially devastating tsunami

The people of Whittier have been aware of tsunamis for generations In 1964, the Good Friday earthquake was followed by a 25-foot wave that crushed waterfront infrastructure, lifting and twisting lines railroad and bringing them back to the sea The Good Friday earthquake – which killed 13 people here and caused $ 10 million in damage – is still in Whittier’s memory

With tons of rocks and rubble perched above a nearby fjord, poised to crash into the sea, the city’s present is shaped both by its past and by preparations for a uncertain future This destabilization is due to climate change: tsunamis are more and more likely in Alaska as the hillsides, once reinforced by glaciers and solidly frozen ground, loosen their grip on once stable slopes

On May 14, a press release from the Alaska Department of Natural Resources and a public letter from 14 scientists warned residents of a possible landslide-triggered tsunami Alaska has identified three similar events in the past: tsunamis in 2015 and 1967 occurred in remote areas, while one in 1958 killed two people whose boat capsized But the unstable slope of Barry Arm, a narrow, steep-sided fjord in Prince William Sound, is far more dangerous The potential energy of a catastrophic slide here is about 10 times greater than previous events, the state’s top geologist said in the May press release

The Barry Arm landslide has been heading towards the ocean since at least 1957, when the Barry Glacier – which once gripped the base of the mountain and held the slope – first pulled its wall of ice load-bearing from under the rocks slope As the glacier retreated, so did the slope support system – dragging the rock face down towards the ocean, leaving a distinct zigzag indentation in the hill Between 2009 and 2015 Barry Glacier has retreated past the lower edge of the landslide and the slope has dropped 600 feet Since 2006 Barry Glacier has retreated more than two miles Scientists estimate the slope will likely fail in the next 20 years – and could even do it in the year

Climate change makes land more unstable and increases risk of tsunamis caused by landslides As the climate warms, glaciers melt and retreat, retreating from the sides of the mountains they hugged The wall of ice the Barry Glacier – which once held the hill in place, propping it up against the mountains of the fjord – has thinned out, moving away from the rock face, releasing its support and revealing an unstable slope that glides towards the Brentwood Higman Ocean, geologist and executive director of Ground Truth Alaska, works with other scientists to study the impact of climate change on landslide tsunamis “[These events] are worth worrying about regardless of climate change,” said Higman “But there are a number of reasons to believe that climate change makes them much more likely”

As glaciers retreat, the land above them also becomes more unstable The craggy alpine region of south-central Alaska is already thawing dramatically Patches of rock, dirt and ice once jellies release trapped liquids and become more and more prone to slide in the mountains

Another less obvious symptom of climate change increases the risk When there is more water in the atmosphere, precipitation becomes more intense Rain, even more than earthquakes, is likely to trigger landslides landslides, Higman said Climate change will make landslides more likely and more frequent, said Anna Liljedahl, associate scientist at Woods Hole Research Center “This is a new emerging danger, and this is why there is an urgent need to make an assessment of where these unstable slopes are located and where they pose a danger to people,” said Liljedahl

Tracking unstable slopes can give local governments time to install warning systems Scientists are therefore working to identify unstable lands, focusing on monitoring landslides near communities in southeast and south-central Alaska.

In mid-October, Gabriel Wolken, Climate and Cryospheric Risk Program Manager for the Alaska Geological and Geophysical Survey Division, took a helicopter to Barry Arm From the air, he conducted a lidar survey, using a laser scanner to measure the topography of the landslide area in great detail, calculating how the landslide has moved and changed since June. The data is still being processed But, there is new rockfall in the area every time he visits, indicating the instability of the area “The rock itself is not very proficient”, Wolken said “He’s falling apart”

The people of Whittier are aware of the risk, said Peter Denmark, who runs a commercial kayaking business in town. “With the people around town there is a laissez-faire attitude about it,” Denmark said. Alaskans have “thick skin” in disaster, he said. It’s not tsunamis, earthquakes, volcanoes, forest fires, it’s one thing or another. ”Yet Denmark is taking precautions; he avoids the Barry Arm area on kayak tours

Kelly Bender and husband Mike rely on summer tourism in Prince William Sound From their waterfront office, she charters water taxis, fishing boats, kayaking and sightseeing tours Before As news of the potential landslide broke, Bender said his fleet entered Barry Arm daily.With its scenic location, near glaciers and a popular beach, the state estimates that 500 people could be in the area at any time during high tourist season Bender changed sightseeing routes, canceled water taxi trips and even canceled a planned wedding. “The danger is that people feel like ‘we know what to do in a tsunami’,” Bender said. That’s the commercial part that we all really are, you know, hanging on a thread. “When the tsunami warning sirens go off in Whittier, the locals know to get away from the coast quickly and head for higher land State encourages coastal residents to keep a ‘carry bag’ full of emergency supplies and plan evacuation routes

While it is still possible to avoid or mitigate many of the worst impacts of climate change, there really is no option to eliminate tsunamis generated by landslides The state uses howitzer cannons to unleash controlled avalanches in rail and highway corridors, but there’s no easy way to gently coax a colossal landmass from the side of a mountain and into the ocean “It’s pretty much science fiction,” Higman said Smaller landslides could be stabilized from the bottom up, but large landslides, like in Barry Arm, “forget it,” said Liljedahl

Improving preparedness, installing a robust surveillance system on and near landslides and creating an effective localized warning system are the best ways to protect communities, she said. Some locals, like Denmark, the kayak outfitter, however prefer a faster approach. “My idea was to just blow it up and avoid it,” he says “But no one thought it was a good one. idea “

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World News – FI – Climate change heightens tsunami threat in Alaska

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