Here’s the scenario: Three young skiiers get trapped on a chairlift right when their ski resort closes for a week; they have no cell phones (and if they did, we’re sure they wouldn’t work), there’s a storm a’comin’ and there’s bloodthirsty wolves lurking about (which is a hazard at most ski resorts, believe it or not). What the hell are they going to do, just sit there and freeze to death? That actually might end up being the more desirable fate in this surprisingly skillful thriller, which trumps its various absurdities and contrivances with a genuine sense of old-fashioned white-knuckle suspense. If nothing else, Frozen is a genuine improvement from writer-director Adam Green’s cheeky slasher debut, Hatchet — it’s basically Open Water in the snow and, more often than not, it works.