The little Graptopetalum paraguayense,they are the little gray/white succulent plants in front of the Agave.
How far into the winter and what temps do you think will mush them?
I bought mine from Plant Delights nursery. They have them rated to z7b. I am guessing at 20F or high teens their gone. And should come back as long as the temps don't drop below 10 for too long. But they are succulent and I think our winter precip will make them a z8 plant.
I agree with Chadec, looks like upper teens might be their limit for staying green. Maybe if snow crushes them really hard then it might brown sooner than that. Looking forward to hearing how they do for you!