The film Turist (Force Majeure) chronicles a family on skiing holiday in the Alps. It's mostly a pretty "ordinary" film with no surreal elements.

But the ending completely bewildered me. The tourists are in a bus, driving back from the hotel after their holiday. They are on a high mountain pass (looks like Passo dello Stelvio), and all the snow is gone. This scene is clearly shot in summer, there is not a single patch of snow on the mountains, and at some point they leave the bus and walk on the road, without their coats on. Initially I thought, what a terribly sloppy mistake. But shooting a summer scene requires the entire film team to come back 6+ months later, and according to the credits, it is indeed shot in a different country. So it must be on purpose. The scene appears surreal to me, although none of the rest of the movie is.

What is the meaning of this scene?