Pretty good with some clarifications needed.
"As the expedition ascends, each explorer gains supplies (cards), at a rate of one per level.": This is misleading. It sounds like you only get one card each hand, but the total dealt cards (starting hand size) increases.
"may travel individually or as teams of 2 in an expedition of 3 to 8 players": It's not clear how teams work. Are they decided once for the whole game or at every altitude? You can't have equal teams of two with three players. (It's not necessary to repeat the player count.)
1. Deal: Do you shuffle the cards each round or use them until the pile runs out?
2. Trump: "If the card is a Yeti or a Yak, the dealer must choose Trump": not just choose, but declare.
"If the Blizzard or Avalanche is turned up": This should have a bullet point.
3. Bid: "This rule ensures at least one person or team will be set every hand." Define set.
Card Values: "Trump beats all other suited cards": Emphasize suited.
Specialty Card Rules: Mention that they can beat trump.
Monk, Blizzard, and Avalanche: I would say they have a value of 0 and the monk wins the trick only if everyone's card is a zero.
The Blizzard card doesn't seem very worthwhile. How often does someone play the exact card the person chose? Do you keep the blizzard out to remind people on subsequent tricks (Especially if you're at a high altitude)?
Avalanche: "can only affect play at the current Altitude Level": This is extraneous, since its effects are immediate.
"If a Yeti or a Yak leads off a trick, then the other explorers do not have to follow suit and may play any card they like in that trick.": Then how do you determine who wins the trick?
Scoring: "Everyone should keep the tricks they win in front of them in separate piles so they’re easy to count. If playing in teams, one explorer should keep all tricks won by his team." This should be earlier when you describe winning a trick.