In the vein of Survive (or Alive, if you saw it in the 70s like I did), The Canyon traps human beings in unforgiving terrain only to push the limits of survival. There are a couple of really shocking scenes here, one involving a rattle snake and another very disturbing one involving an amputation, but if the kids close their eyes for a few minutes there isn't anything else that would make this anything but a PG film. Some of it isn't very plausible, in fact the entire idea of the heroine suddenly becoming Grizzly Adams and fighting off wolves with her bare hands, creating a stretcher out of thin air, cauterizing a wound with a red hot knife, and keeping her beauty and sense of humor through it all, is actually pretty ridiculous if you think about it, but it doesn't matter that much: this is a disaster movie of sorts, so don't think about it. It'll keep you going, keep you interested and engaged, and from time to time it will make you cringe. But, be warned, the ending is the anti-climax of all anti-climaxes.