I happened to accidentally catch the Norwegian disaster movie The Wave a couple of weeks ago. It's about a potential disaster so likely that all of the settings are real. The Norwegian village Geiranger sits at the end of a picturesque fjord (appropriately named the Geirangerfjord), and it looks like this:
That picturesque beauty is also the danger. The danger exists because those steep fjordwalls (I made that up) occasionally experience fjordslides (OK, that's enough), when part of the wall just lets loose and slides into the fjord, making a big fjordsplash. And that splash would travel straight down the narrow walls of the fjord into downvillage Geiranger.
(Sorry, couldn't help myself, I had to write fjordsplash.)
A better name for fjordsplash is tsunami. And this danger is so real that Geiranger has sirens that are ready to go off in case a fjordslide is detected, to warn the residents to head to higher ground before the landslide-caused tsunami shows up.
It can happen and does happen (the link goes to an article about the landslide in Taan Fjord in Alaska, which created a wave about 193 meters, about 600 feet, high). It's probably more likely than a massive lahar releasing from the summit of Mt. Rainier, and geologists know that has happened too. (And there are warning systems for communities that might be affected there, too.)
So, yeah, The Wave could happen. Below is a still that shows the movie's depiction of it happening:
The lead actress was Ane Dahl Torp [IMDb link], shown below. By the way, she was also in a movie called The Quake, about an earthquake hitting Oslo, that doesn't seem nearly as plausible, and I think it's the same characters (her and her movie family), which is even less likely. I'm skipping that one.