Ice Melt in Alaska Threatens to Unleash Unprecedented 'Mega-Tsunami', Scientists Warn

A giant, catastrophic tsunami in Alaska triggered by a landslide of rock left unstable after glacier melting is likely to occur in the next two decades, scientists fear - and it could happen within the next 12 months.


A group of scientists warned of the prospects of this impending disaster in Prince William Sound in an open letter to the Alaska Department of Natural Resources (ADNR) in May.


While the potential risks of such a landslide are very serious, there remain a lot of unknowns about just how or when this calamity could take place.

What is clear is that glacier retreat in Prince William Sound, along the south coast of Alaska, does seem to be having an impact on mountain slopes above Barry Arm, about 97 kilometres (60 miles) east of Anchorage.


Analysis of satellite imagery suggests that as Barry Glacier retreats from Barry Arm due to ongoing melting, a large rocky scar called a scarp is emerging on the face of the mountain above it.


This indicates an incremental, slow-moving landslide is already taking place above the fjord, but if the rock face were to suddenly give way, the consequences could be dire.


Although it's remote, this is an area that's frequented by commercial and recreational boats, including cruise ships.


Pale scarp lines above Barry Glacier. (Lauren Dauphin/NASA Earth Observatory/USGS)


"It was hard to believe the numbers at first," one of the researchers, geophysicist Chunli Dai from the Ohio State University told NASA's Earth Observatory.

"Based on the elevation of the deposit above the water, the volume of land that was slipping, and the angle of the slope, we calculated that a collapse would release 16 times more debris and 11 times more energy than Alaska's 1958 Lituya Bay landslide and mega-tsunami."


Tsunami projections. (Briggs et al., open letter to ADNR, May 2020)


"It's really pretty terrifying," Higman told Columbia University's GlacierHub blog in May, likening the environmental risks to volcanoes – something that humanity has understood to be a dangerous, unpredictable geohazard for much, much longer.

"Maybe we're entering a time now where we need to look at glaciated landscapes with the same kind of glasses."


The findings are available on the ADNR website.

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