Originally posted by ÆAsphyxia:

They're also required for progression. This isn't minecraft; we can't climb sheer faces by jumping from block to block. There's no excuse for why the mountains are so sheer and difficult to access. I spend most of the time fighting the mechanic that slides the player down hill. That's not good gameplay.

...You have a pick. Sprint/jump up the mountain till your stamina drops to 20, then swing the pick to create a foothold. Repeat until you reach the summit. Also last I checked silver armor still blocks the cold? Just make sure you're dry before you start climbing.