Some good news and some bad news.
Good news is I solved the belt problem to some extent utilizing a steeper helix and lighter primary weights coupled with an almond spring and a stiffer secondary spring. Problem for me was the secondary wasn't "grabbing" the belt.
To add, keep that belt deflection in check. If its loose, you'll burn the crap out of belts.
Bad news is, if you are running a turbo and often wide open in deep snow, heat will be a problem to some extent (no matter what). So far I haven't blown a belt in 2017 - but I have a sneaking suspicion I will be soon!
Like the others hinted, you were always starting out in second gear. Find a replacement for the almond as soon as you can. They work good only for a little while then sack out, in my experience. I'm not fond of 10 series weights either. 11 series or MTX or any other heavy heel weight would be better and at least load it harder down low... 10's don't have any belt clamp until you open the primary about .200" so you need to balance it with a secondary that barely allows that before stiffening up.
5psi ain't that much boost at altitude so it's not like you got big power and a special issue, u just need to get your clutching and gearing in order.