Every char should get skis or SS (can be improvised from few spruce twigs) in winter. How get the njerp there in the first place and why is he so pantsy in winter after few steps?
As someone who's made attempts to manufacture snowshoes at home, in the most traditional way possible, I'm also willing to speak up for snowshoes. Though we might need to look into potential historical accuracy issues (I know URW isn't historical, but
it is Finnish-inspired), I think snowshoes would be a wonderful addition to the skis.
They'd be slower (basically average walking speed, no speed bonus), but maybe they could help diminish a player character's fatigue from walking in deep snow. That seems like a logical in-game justification for them, at least as far as I'm concerned.
Concerning what cultures you could find them in and buy them from, I think it's rather predictable they'd be the most common among the Northern Region tribes. I don't know how common or uncommon skiis are among all of the cultures in the current game, but if there's already some variation in the quantity of ski usage by the different cultures, it could make sense for there to be some variation in snowshoe usage as well.