ALASKA

ALASKA Thora Birch, Vincent Kartheiser (1996, Columbia TriStar, PG, priced for rental) ''A missing father. A desperate search. An unforgettable adventure.'' But what the video box for director Fraser Heston's family flick should read is ''Kids, don't try this at home!'' Dissatisfied with rescuers' attempts to find their father (Dirk Benedict), trapped in his plane after surviving a crash, a troubled teen (Kartheiser) and his sister (Birch) ill-advisedly set out to find him, armed with marshmallow pies but no matches. Luckily for everyone, a frisky polar bear cub, whom the kids free from a poacher (sinisterly played by Heston's dad, Charlton), saves the day. But the cub's inspired performance, and the film's breathtaking scenery, do little to make this an incredible journey. C+