Arctic
Source GM Core pg. 93
The main challenge in an arctic environment is the extreme low temperature, but arctic environments also contain ice and snow. The disasters that most often strike in arctic environments are avalanches, blizzards, and floods.
Ice
Source GM Core pg. 93
Icy ground is both uneven ground and difficult terrain, as characters slip and slide due to poor traction.
Snow
Source GM Core pg. 93
Depending on the depth of snow and its composition, most snowy ground is either difficult terrain or greater difficult terrain. In denser snow, characters can attempt to walk along the surface without breaking through, but some areas might be loose or soft enough that they're uneven ground.