According to the film's creator, it is partially based on the book "The Strangest Story Ever Told" by Harry Colp. The book has, for decades, had an intense, cult-like, following in Alaska. It's a book that you do not want to read after dark, in a tent, in the wilderness.
Snow flurries falling during Margarette's last scene were unintentional. It started when she appeared and went away by the time the scene was done. The Director thought it was so cool, he didn't retake the shot. It fittingly ties into the characters death at the start of the film.