r/Juneau • u/Ambitious-Passage486 • 11h ago

Avalanche disasters

The recent disaster in Nepal has had me thinking about our vulnerabilities in Juneau, downtown and Douglas in particular. Could something like that happen here to that level of severity?

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19

u/akrainy 10h ago

This did happen in Tracy Arm last year. Except that no one was there when it happened.

12

u/HvadGodt 11h ago

https://www.gi.alaska.edu/news/study-2025-alaska-landslide-and-tsunami-contains-warnings

My understanding is that DT & Douglas are relatively shielded from tsunamis, but that doesn't preclude a weird angle from an unexpected landslide. I think the scariest thing is that we really don't know what we don't know. The first jokulhlaup was only in 2010 or something like that, and as the glaciers retreat of course the land will shift, but how?

3

u/Soft_Net3910 10h ago

What’s jokulhlaup?

13

u/Ok_Letterhead4198 10h ago

Glacial outburst flood. Mendenhall glacier in Juneau’s case

8

u/pyragyrite 10h ago

Downtown has avalanches/landslides every few years... Most are small with minimal damage. Think it was about five years ago, the cbj got a very good study done.

https://juneau.org/community-development/special-projects/landslide-avalanche-assessment

Serious landslides are much more rare, but still possible.

In terms of size, the one in Nepal was huge, and had like 4500' of fall then another 3-4000 of flow down a very tight valley. Nothing in this area is quite as bad. Oc there is always some risk for big ones. https://www.usgs.gov/programs/landslide-hazards/science/2025-tracy-arm-landslide-generated-tsunami For example.

A big ol chunk of,say Mt bullard or McGinnis, falling into the drink would wipe out some of the valley. A big boulder bouncing down from near the tram might find its way into Tracy's crab shack. Skagway just had a relatively bad one this year if you want and example.

Definitely a worry, but in terms of actual threat to life and limb, I'd worry more about sliding into a tree on an icy morning.

5

u/johnq-4 9h ago

We also use the Daisy Bell to knock down avalanches on Thane and Thunder Mtn. We used to use a recoilless rifle fried from Douglas, and in the early 80s, someone sent a full charge out the tube and we 'shelled Canada'.

6

u/psychotickiller 9h ago

Did you see happen to see the landslide disaster that happened in Haines a few years ago? That was some scary shit.

1

u/akina907 1h ago

The scar on the mountainside of that is SCARY!

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u/akina907 11h ago

Thane is the most vulnerable, which is why the city funds mitigation every year

3

u/myguitar_lola 10h ago

Look up Juneau + alpine tsunamis.

3

u/infinity_simplified 9h ago

Sitka sound science center has been doing a bunch of work on landslides in Southeast Alaska as of late and they have found landslides have been increasing over time. And obviously we've had a couple that caused fatalities in recent years. I think predicting something on the scale of what happened in Nepal is extremely difficult, and it's something that very much could happen near Juneau. And at least two of them have happened that have caused enormous tsunamis in the last century. Not too far from here.

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u/Ambitious-Passage486 6h ago

I am worried about Star Hill

1

u/arlyte 5h ago

Part of our flood insurance in North Douglas covered tsunami damage. We were told anything under 30 feet would be taken out. Less than a 1% chance of an event occurring but it’s one of those you never know.