On Mars is there an area in which all the $CO_2$ evaporates exposing dirt near the pole? How deep can solid $CO_2$ accumulate during winter in that area during the Martian Winter?
1-2 m in the north and 8m in the south. https://en.m.wikipedia.org/wiki/Mars#Physical_characteristics https://en.wikipedia.org/wiki/Martian_polar_ice_caps#North_polar_cap
It is the northern cap that disappears in summer.