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Residents, recreationists asked to employ continued caution as Barry Arm landslide threatens Whittier, surrounding area

Alaska Earthquake Center photo of area near Barry Arm.
Alaska Earthquake Center photo of area near Barry Arm.(Alaska Earthquake Center)
Published: Jan. 16, 2021 at 5:35 PM AKST
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ANCHORAGE, Alaska (KTUU) - Researchers doubled down on their warnings Thursday of the potential for a massive landslide in the Barry Arm area, about 30 miles north of Whittier in Prince William Sound, and the adverse effects that could come with it.

“There is instability here,” said Bretwood Higman, a geologist with a propensity for data visualization who spoke at a public meeting Thursday evening. “It is actively moving. And it’s very large.”

Several of those who have studied the area said Thursday that if the 1.4-square-mile slide lets go, it could produce a devastating tsunami that could quickly make its way through nearby communities. Some of those same experts also said they’re doing all they can to make sure people are aware of what’s going on as scientists work toward implementing an early warning system.

According to researchers, if the slide releases, waves from a resulting tsunami could push past 30 feet high, threatening any of those recreating or living in the area. With the unstable slope located on the west side of Upper Barry Arm near the terminus of Barry Glacier – in northwest Prince William Sound – the danger is particularly threatening to those around Whittier, but also in towns such as Chenega, Tatitlek, and Cordova.

The threat of landslides is not new and there are many unstable areas in the fjords surrounding Prince William Sound, presenters said, but the size, location, and potential damage this particular threat might cause could be devastating. Per DGGS, data collection that has already taken place indicates more movement over short periods of time that appears more rapid than in years past, as well, though the overall landslide rate seems to have slowed since 2016.

“Between 2009 and 2015, the landslide moved 600-feet toward the fjord at the same time as Barry Glacier was thinning and retreating below the landslide,” according to DGGS, which also noted that motion of this particular slide may have begun as early as 1957. “Landslide motion during the period June through September 2020 was less than a few inches, but between October 9 and October 24, eight-inches of downslope motion was detected.”

During Thursday’s meeting, people were asked to please heed any posted warnings – for example, to avoid any activities in that section of Prince William Sound – and remember that nature’s warnings may be peoples’ only alerts.

“If you feel a very strong earthquake, if you see water withdraw or advance at an unusual distance or hear a strange rumble or roar,” said Dave Snider, National Tsunami Warning Center Tsunami Warning Coordinator, “that is a warning sign that you need to move to higher ground immediately.”

As it stands, much remains unknown about the timeline of any potential natural disasters within Barry Arm or the steep slope threatening to fall into the water there.

“We’re really focused on gathering important data, baseline data,” said Gabriel Wolken of the Division of Geological and Geophysical Surveys, “that’s necessary for us to characterize the last and current state of unstable slope in Barry Arm.”

Geologists have been able to clearly identify the area and region at risk of landslides, the Department of Natural Resources Geological and Geophysical Surveys said, but “there is much they don’t know about the situation.”

“It is difficult, if not impossible, to predict with any degree of certainty,” according to DGGS. “Scientists are working to gather what information they can, to help them better understand the risks, and to better guide any emergency communications and response.”

As more data is collected, one thing remains certain: the danger of a slide emanating from above Barry Arm is real, but so too is the effort to at least mitigate it. However, help could be on the way soon in the form of monitoring equipment, such as tsunami gauges.

“We expect to do our initial installation and testing of the monitoring equipment in the spring,” Snider said, “and into the summer of this year. So summer of 2021.”

The state has recommended that in the case of the Barry Arm landslide tsunami risk, people should participate in community meetings as much as possible. To prepare for both specific and general tsunami threats, residents in tsunami-prone areas should make easily accessible “go bags” that include emergency items, such as food and water servings and doses of prescription medicines; review the ways emergency alerts would be disseminated, including through Nixle notifications, tsunami sirens, and phone communications; know the signs of an impending tsunami, and be aware of and practice emergency routes for yourself and with any family or household members.

Read more about the Barry Arm landslide by clicking here.

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