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Then I would advise wearing whatever you feel comfortable with and having a disposable mask in your pocket just in case there's a jobs-worth or inspector about. In any resort I've been in this season, as long as the building isn't fully closed, they haven't been enforcing anything. Verbier / Zermatt etc base stations are probably a bit more picky as they'll have more pressure on them, but smaller ones are still very casual.
Really anything will do. It's only in the closed stations that they are 'mandatory' and any kind of Buff or similar will be accepted in reality. If you are concerned about it being effective, then just take a pocket full of disposable masks and put it on only when necessary. When skiing, any face covering gets so damp that I think it would be wildly inneffective at protecting against virus transmission.