Ground Truth Alaska

09/30/2024

If you live somewhere up along the Glenn Highway, please consider joining us for an evening event on Oct 23 (Glacier View) or 24 (Wasilla) to discuss how we might reduce the risk of landslide disasters in this area!

09/12/2024

I was interviewed by NBC about a recent publication on last year's tsunami in eastern Greenland - I didn't work on that event, but the reporter gave me a chance to think out loud about how the risk of landslide tsunamis may be increasing:

The tsunami, one of the largest ever recorded, was the result of a series of rare, cascading events set in motion by melting ice.

08/27/2024

A couple things about the big rain earlier this month:

Several people let me know that a lot of debris came out of the Seldovia River during the big rain on Aug 6-7. I finally had a chance to dig through satellite imagery to look at what might have been going on, and it looks like the answer is probably that it was simply a really big flood, so the river moved around in the area where it has the most room to do so - the cottonwood flats about halfway down the river. If you open this imagery comparison, you can slide the wiper in the middle back and forth to see that the channel changed substantially in that area. Looks subtle from space, but if you were there in person it would be quite dramatic.

I don't see any landslides, though there may well be small ones that I can't pick out in these images. If you hadn't heard, there was a significant landslide-generated tsunami that happened early on the morning of the 7th at upper Pedersen Lagoon near Aialik Bay, west of Seward. Presumably this was triggered by the heavy rain. The tsunami crossed the upper lagoon, and was likely 30-50 feet high at the far end where it flattened large areas of alder forest. It ran down a slough that's about a half-mile long, then crossed the lower lagoon and did minor damage to a lodge there, where the wave was probably 2-3 feet high. Though the rain was the immediate cause, the landslide and tsunami were in places that were buried in ice just a decade ago, so glacial retreat was a critical ingredient too.

https://www.planet.com/stories/seldovia-river-cottonwood-flats-changes-early-aug--93rS1t3SR

Valisa Higman Lisa Stanish Erin McKittrick

06/05/2024

Vessels and tsunamis (and me) in the news!

Tour boat operators and cruise ship captains face a growing hazard: tsunamis generated by collapsing cliffs. If disaster strikes, what should they do?

04/22/2024

Over the past few years I've spent a lot of time looking at satellite imagery and other datasets to identify signs of slope instability as well as past giant landslides in Alaska. This morning I added the 1000th row to my data table, so I thought I'd share what I found here:

This landslide falls into the most common category of recent giant landslides in Alaska - a high alpine slope (part of Mount Huxley) that collapsed onto a glacier. You can see the deposit of the landslide in the image available at the link below. It was a slope just above a glacier that's been thinning (like most glaciers). Many of the landslides in this area are on north-facing slopes, but this one was south-facing.

When I say "giant" I'm not using this in any technical sense - this one is probably around 1 or 2 million cubic meters, which is certainly giant if you were there to see it, but actually on the small end of the landslides I've been focused on. The largest landslides that have happened in the past decade in Alaska are over 50 million cubic meters, the largest in the world are more like 250 million cubic meters, and as you go back into the past few thousand years you get into the billions of cubic meters.

This landslide happened in a place far from where people live, and high above the water so there was no risk of a tsunami. Fortunately this is where the majority of very large landslides happen. However, not all are so isolated - part of the work I'm doing hopes to use these more common remote landslides to understand the really consequential ones that are closer to home.

Also it's important to remember that sometimes there are people in these remote places - I would love to get to the point of having more useful guidance for mountaineers and other wilderness travelers about how to avoid this sort of event, especially since they seem to be getting much more common!

Wayback imagery is a digital archive of the World Imagery basemap, enabling users to access different versions of World Imagery captured over the years. Each record in the archive represents World Imagery as it existed on the date new imagery was published. Wayback currently supports all updated ver...

04/03/2024

If you missed my presentation in Homer - it's now posted on YouTube. Comments welcome!

Hig (Bretwood Higman) presents on how climate change is presenting new challenges for addressing geologic hazards. The discussion includes looking at the his...

03/14/2024

I'm still making a few tweaks to my presentation happening this Sunday (5:00 in room 201 in the Kachemak Bay Campus of KPC in Homer). I practiced it last night and it's a bit long, so I'm looking for places to trim. I think these three slides will be making the cut though.

At the end of my presentation I will be talking specifically about landslide hazards in Homer. If you have a perspective or question on this topic, it would be great if you could put a comment in to help me figure out how to best frame what I present.

03/04/2024

Homer friends - I'll be presenting the keynote for the KBay Science Conference in room 201/202 at the college, at 5:00 on March 17. Here's my title slide - I welcome speculation in the comments!

02/23/2024

How's your French? Practice a bit and learn about the study of permafrost degradation and its influence on landslides in Alaska.

L’Alaska subit de plein fouet le changement climatique. Mais avec la hausse des températures, le pergélisol se dégrade. Sans cette couche de glace sous terre...

01/25/2024

Friends, please take a minute to submit a comment to the BLM regarding their consideration of loosening protections on 28-million acres of public lands in Alaska. As we all know, Alaska is being sized up for a new extractive minerals boom. The removal of these protections would be devastating. Another point to be aware of is that if these rollbacks occur, rural Alaskans will lose their rural subsistence preference ights.

Comments are due by February 14th. Here is the BLM's comment portal:
https://eplanning.blm.gov/eplanning-ui/project/2018002/595/8020037/comment

Although I think these sort of petitions are basically useless, here's one anyway:
https://www.alaskalands.org/take-action

If you can only muster a few words, please make them be: BLM, support the no action alternative regarding the ANCSA 17(d)(1) Withdrawals Draft EIS.

Quyana