McKinney Bay Landslide
The McKinney Bay Landslide was a prehistoric underwater landslide in Lake Tahoe that triggered a massive megatsunami between 12,000 and 21,000 years ago
Made with AI
The landslide
Tens of thousands of years ago, a huge piece of Lake Tahoe's west shore at McKinney Bay broke loose and slid into the lake. It was too long ago to pin down exactly when. Estimates of its size run from about ten to fifteen cubic kilometers of rock and sediment. Blocks the size of buildings, some more than 300 feet across, ended up spread across the deep floor of the basin. At its deepest, the lake is about 1,645 feet deep.
The side quest
I wanted A.L.T.A. to go and look. So I put together a side quest for her, writing the dossier and the script with AI: Echoes of McKinney: The Abyssal Scan. It is told from the point of view of a small research drone tagging along behind her. It runs in five acts: over the drop-off at the edge of the Tahoe City Shelf, down into the dark, an inspection of one of the megablocks, a scan along the fault, and the climb back up toward the light. The telemetry in it is story, not data. Nobody has actually checked the basin with a brass mermaid.
Nobody has actually checked the basin with a brass mermaid.
The wave
The slide pushed a wave across the whole lake. Nobody can say for sure how tall it was, but it was big enough to wash over the shallow Tahoe City Shelf. A 2006 study looked at long boulder ridges on that shelf, one to two meters high and up to two kilometers long. It read them as giant ripples left by the currents the landslide set off. The same study points out that the part of the sediment bench that didn't collapse could fail again someday. The West Tahoe–Dollar Point Fault still runs along the base of the slide zone.
The dive
Over the edge of the Tahoe City Shelf and down the Dollar Point drop-off
Into the twilight graben; the first sonar ping finds the megablock field
Anchored above Megablock Alpha, a brass hand on the granite
Along the West Tahoe–Dollar Point fault: the western slope is holding firm
Scan complete, lidar retracted, a spiral turn and the climb toward the light
The pictures
Every picture here is made with AI, built on some real facts but not a record of anything. They came from five image prompts, which AI and I wrote together: a bathymetry chart of the collapse, the descent past the shelf edge, the megablock inspection, the fault scan through a drone's HUD, and the ascent. Each one has a partner prompt that turns it into a ten-second video loop.
I also rendered two versions of the wave reaching Sand Harbor on the east shore, just to show what it might have looked like. One is a photo-style shot of the water coming over the granite boulders and coves. The other is a simulation on a research screen.
They all go together in the spread below. It opens with the holographic lake and its fault lines, which show where the side quest is headed and set up the dive. The dive itself sits in the middle, and the wave at Sand Harbor comes at the end.
What I learned: opening with the map and the overview, so you know where the story is going before it goes there, makes the middle easier to follow.