This looks truely amazing, I made the same kind of mission back in A2 days where you had to destroy an antenna on top of Mt Cook.
Thank you for bringing the memories back.
By the way, you might be interested by this:
This is a basejump script I made for this map, we had great fun with it. I had a better video on the latest version but it got removed from youtube. Anyways, if you're interested I will give you the script with great pleasure.
Edit: Few things that went through my head while playing:
I had a script error when calling foggybreath.sqf, replace this by player. ([player,0.1] execVM "foggybreath.sqf"; ).
The little flagpoles to indicate the way to the top are cute but I think a rock formation (cairn) would be more accurate (I live in the alpes so this tickled me).
Also, in my opinion, you'd have to add more distance in between two flagpoles, otherwise it feels really easy to just follow the path (maybe it's intended).
The avalanche is great, maybe you'd like to hide the cannisters (it felt weird to me) using hideObject.
You might want to take a look at NIM weather for A2, I know it had some great blizzard effects.