1. When it says in the rulebook that two skiers going at the same speed, their movement is resolved 'back to front' what does that mean?
It means whoever is behind in the race. So as you're racing down the mountain towards the final card, whichever skier that is furthest away from the end is in the back and would move first.
2. Also, is there anything stopping you from being over taken by the avalanche on turn one? We had that happen after two skiers used their rockets in the opening turn (one with a wild and one by matching the symbol of the first card of the mountain), opening the avalanche speed to two, and the third player got over run by it. We just restarted, but was wondering if there was something in the rules to prevent that happening that I missed.
You can't rocket jump on the first turn. Skiers start the game in a line next to the first card, not on the card, and because you rocket jump by matching the symbol of the card you occupy when playing the card (or by playing two cards of the same type), it is impossible to rocket jump on the first turn. The first time you can rocket jump would be the second turn.
Hope that helps!