About 2 weeks ago we had several inches of snowfall over a few days. Cold settled in right after, and the snow stuck around for a week. The snow on the garden beds was about 6 inches deep for that period. I am happy to say that the mache survived. I picked a large handful of leaves to add to a salad for lunch the other day, and there's still plenty out there. Between the mache, the Brussel sprout greens, and the kale, I'm still able to harvest greens from the outdoor garden several days each week.
We may have snow again next week. So we'll see how mache does with repeated snowfalls.