The June edition of National Geographic features a story on Seldovia geologist Bretwood “Hig” Higman and his research work on glacial landslides on Alaska’s Kenai Peninsula. Portage Glacier, located 55 miles southeast of Anchorage in the Chugach National Forest near the community of Whittier, is the key glacier in the story “Lessons of a landslide detective.”
The lead for this story: “across our warming world, the ground is growing less stable. Nowhere is the problem more evident than in Alaska, where one maverick geologist is now on a mission to discover where the next big disaster might strike.”
Christian Elliot, independent science journalist pitched this story to National Geographic last year and came up to Alaska from Illinois to shadow Hig on his research work with some of the glaciers in southcentral Alaska.
“This is a story about giant bedrock landslides in Alaska. We do not refer to landslides as many people think of them, like the fast-moving mud and rock landslides that happen after a heavy rain in southeast Alaska. These are literally mountainsides and cliffs collapsing all at once, and they can fall into lakes and into fjords, and when they do that, generate giant tsunamis. We've seen this happen in Alaska recently, recently last summer in the Tracy Arm Fjord. This is an emerging climate-linked geohazard, as glaciers retreat and permafrost thaws the material that is holding these rocky cliffs and mountainsides up and keeping them frozen in place, it's going away increasingly, and the mountains and cliffs are becoming more unstable.”
The National Geographic article is 28 pages long and full of details and hazards related to glaciers in south central Alaska. Other than Portage, some of the key sites it focuses on are Surprise Inlet, Barry Arm and Port Wells in Prince William Sound. Barry Arm is 40 miles southwest of Whittier in Prince William Sound and a landslide there could generate an initial 500 foot wave, giving Whittier residents 20 minutes to evacuate uphill. However, as the article notes, if the summer cruise ships were docked at the town terminals, several thousand people would be at risk. Another location focus in the article is Glacier View, Alaska in the Matanuska Valley and the Victory Bible Camp, potentially in the pathway of a landslide.
Elliot described some of the features of the Begich Boggs Visitor Center in Portage are still transitioning this summer:
“Hig’s instruments are still a work in progress, so they're working on getting data from those instruments down to the visitor center in Portage, and the US Forest Service there already has a system where they keep an eye on rock fall and heavy rains and other factors that can trigger a landslide to make sure they can close the visitor center and tell people to evacuate if landslide risk is creeping upward. Hig’s instruments are in the process of being included in that system.”
This is a description of the Portage project in Higman’s terms:
“…I've been working for the last few years at Portage, which initially was sort of an academic project. We started realizing this is this maybe one of the places in the state where there's most, the most coincidence between dangerous landslides and where there's lots of people. So we've been trying to transition into doing something a little more, more valuable for the, you know, like the public and protecting them, so we've been installing monitoring instruments up there. It's sort of a shoestring project, and, and quite experimental. This year we've got monitoring up there, and we're working with the visitor center to help monitor the possibility of a landslide generating the tsunami there.”
Though not part of the National Geographic story, Elliot also described some hazard features of Grewingk Glacier, closer to Kachemak Bay:
“Grewingk doesn't make it into the story, but it's a really interesting place, because that's where Hig first sort of learned about. Of these giant landslides, because one collapsed into the lake as the glacier retreated back in the 1960s. So it's been a long time, but it's pretty clear, because it shows that the rock face became unstable after the glacier backed away from it and retreat, and that's a phenomenon that's called debuttressing, like a flowing buttress that supports a big cathedral, and you take that buttress away and the rock becomes more and more unstable.”
Hig Higman has some additional geologic research projects coming up near Homer in June and explained those in a phone conversation:
“So landslide tsunami’s, you know, Grewingk is kind of the place to talk about there, but landslides in general, there's a lot to think about in Homer. I'll be doing some instrument deployment in Homer on, I think it's going to be on the 11th…so hopefully get out by Bluff Point, and probably up above Woodard Canyon.”
Reporting from Homer, this is Emilie Springer.
