Landslide-generated tsunamis don’t come with any warning signs and they’re impossible to predict. Tsunami scientists are meeting with vessel operators in Alaska this month to put together some practical guidelines for captains to use in the case they encounter one of these snap tsunamis. These recommendations will be useful for the hundreds of tour ships that navigate the large landslide-prone coastlines of Alaska, Greenland, Chile, Norway, and New Zealand. Hopefully this summit will help prepare ships, and save lives in the process. A tsunami hasn’t killed any boat passengers in Alaska in 60 years, but as ice mass continues to dwindle in the face of a warming climate, the probability of a big event increases.
Geologist Bretwood Higman recently spoke with the Atlantic for this piece regarding a potential epidemic of landslide-triggered tsunamis. He knows of dozens of unstable slopes with millions of cubic feet of rock ready to push into a bay or fjord. Any of these tourist ships caught in the area at the wrong time would be helpless to capsize. It would be a freak accident, to be sure, but a potentially devastating and deadly event that bears thought.
“I do think that, at some point, [the situation] is going to explode,” says Higman.
In 2015 the Taan Fjord saw a 2.6 billion cubic feet of rocky land slide into the water in an instant. This sparked a 650-foot tall wave to roar out of the fjord and into Icy Bay. As the water became deeper the wave gathered speed, pushing faster and faster out of the bay and into open ocean. Thankfully no boats were in the bay at the time of the massive wave, but boats do visit semi-regularly.
The National Park Service is particularly concerned with large cruise lines entering Glacier Bay. An average of two ships traverse the bay every day during the height of tourism season, and there are as many as a dozen large slabs of land poised to slide into the water at any given time. If one of those lets go at the wrong time, thousands of people could lose their lives.
Right now the best advice for tsunami avoidance on a ship is to either run the ship aground and hope for the best, or head for deeper ocean and hope for the best. Both of those pieces of advice are based around deepwater earthquake-triggered tsunamis, which typically provide ship captains lots of advance warning. If you have mere minutes to attempt getting out of an Alaskan bay, you don’t have time to second guess yourself. That’s why the summit is so important, providing best practices for ships in the case of one of these freak accidents.
I don’t think I’ll be taking a cruise to Alaska any time soon. That sounds like a horrifying way to die.
