When a family skiing trip ends in the murder of her parents, a sheltered teenager must lead her friends through a blizzard to escape a gang of vengeful hunters.

So her parents were murdered by hunters who were pissed at them about something and who now want to hurt her and her friends as well?

When her parents are murdered during a ski trip, a sheltered teenage must evade mercenaries pursuants through blizzard ?and reach the safety of a resort on the other side of the mountain.

Agree with Craig,

also this is one of those instances (mentioned by Richiev) as having a bigger inciting incident than the plot that proceeds it. Is it possible to not kill the parents in the Inciting incident?
That kind of triggers the 'defeatist' in an audience and they get to think: "it cannot get any worse..." To make it 'page turning' becomes harder

Good Luck The_CNI!