There is very little that you can do to keep mobile home skirting from bending in the cold weather. The main cause of mobile home skirting bending is that the soil underneath expands and contracts as water freezes. The expansion and contraction cause the soil level to rise slightly, making the skirting bend.
In theory, you could cut your mobile home skirting a little shorter, so that when the level of the soil raises it does not meet the skirting, but then when the weather thaws, the skirting will be too short. Remember it is much easier to cut a little off than to put a little bit back on. That would probably require replacing all the skirting, or switching to an alternative.