very weird.
I remember, however, an exhibit in the Science Museum in St. Paul, MN, where a huge bunch of crushed cars were in a big block, with a small device that used compressed air to float the darned thing. The brick weighed a ton or more, but once the air lifted the block a few millimeters, one could overcome the inertia and glide it about with just a finger. Still a lot of inertia to get it started, but very cool how low the resistance was otherwise. Well, if they experience similar conditions and can get back there to set up more cameras to observe. Or maybe the Dept of Interior will allow them to pull on an existing rock to see how slippery it is with the wet clay.
Speaking of that, there is Black Rock Desert that hosts the Burning Man but more importantly, the Large Dangerous Rocket Society, and when it rains even a smidgen, things get all fouled up. I've not been there but heard from an attendee when there was a wee bit of precip that conditions were just absolutely awful.
I think Bonneville has dried salt on the surface and not clay like stuff.
I also remember hiking in Yellowstone and crossing the Snake River three times on our way out. Boulders about the size of bowling balls were on one ford, and the spring melt silt had coated them, and it truly was as greasy as anything I've ever tried to pick up.
So if conditions are right, I guess it might happen.
Did you get to see the video link?
