Theres snow in mountains, this means its cold. And also I can sometimes hear the cold wind blow and the freezing mountain rivers flow.
Maybe you should get frostbites if you stay in the mountains for too long or swim in the cold rivers.
This could be prevented by having proper clothing equipped or drinking hot liquids such as tea.
Also moving in the snow could be crawling or walking speed at the most, this could be made faster by certain type of shoes or skis.