Actor Kevin Zegers did the scene with the wolves starting to swarm around him (just before the actual attack) without a stunt double. When one of the wolves got too close for comfort, the trainers had to pull the wolves away and filming had to stop. In the film you can see a few frames of the black wolf walking right up into Kevin Zeger's face as Kevin tries to look away for help from the crew.
To get the shots of the chairlift moving with the actors speaking on it, director Adam Green and director of photography Will Barratt shot everything themselves as the film's hired camera crew was too nervous to dangle at those heights.
At Sundance Adam Green told a story about how the spot where they shot Frozen was supposedly haunted by a suicide victim who had killed himself in that very spot a year before. This was validated by an audience member during the Q&A at Sundance. She personally knew the victim.
When the wolf takes down actor Shawn Ashmore, it is actually a boarder collie in that one shot. The German shepherd that was trained to do the stunt mysteriously died two nights before the scene was shot.
When trying to find the right spot to shoot the movie, some of the crew were scouting the area from one of the chairlifts. One suggested a spot 50 feet above the ground and the chairlift, almost magically, just stopped. They knew right then and there that this was the right one.
In the scenes where you can see the actor's breath it is early in the night and they were still relatively warm in their costumes. If you can't see their breath it means it was a scene shot much later in the night when their body temperatures had dropped substantially.
Actress Emma Bell was the very first person to audition for Frozen. After sitting through weeks of other auditions, Adam Green hired her for the role as she had set the bar too high for anyone else to compete with.
Filmed at Snowbasin Ski Resort in Ogden, Utah though the story takes place at a fictitious New England mountain called "Mount Holliston". Holliston is the town where Adam Green grew up. There are no ski mountains there.
Frozen's UK Premiere was at FrightFest in Glasgow, Scotland, a festival that Adam Green is very fond of and attached to as he attends the London edition of FrightFest every summer whether he is promoting a film or not.
The first night Dan, Joe, and Parker are on the lift, Joe starts a conversation about the worst way to die. Dan says to him, it would be being eaten alive by a shark, which leads to a discussion of the movie Jaws (1975). One of the production companies for "Frozen" is called "A Bigger Boat", a name taken from Sheriff Brody's line from "Jaws" ("You're gonna need a bigger boat).
The first time anyone ever saw Frozen was at Ain't It Cool News' Buttnumbathon event in Austin, TX in December of 2009. It was a surprise screening where Frozen played alongside Shutter Island, The Lovely Bones, and Avatar. One woman in the audience fainted and was carried out after watching Kevin Zegers' character jump from the lift to the ice fifty feet below.
Twisted Sister's Dee Snider is the voice from the top of the mountain who announces "Last chair is through." Dee's son Cody was the director's assistant on the picture and cameos in the lodge wearing a Twisted Sister T-shirt.
The main characters are named after Adam Green's real life friends "Joe Lynch", "Dave Parker", and "Spooky Dan Walker". Though the names were originally temp names in the first draft of the script, everyone got used to them and they stayed that way for the film. There is a moment when Lynch says to Dan "That's kind of spooky, Dan" as a shout-out to Spooky Dan Walker.
There is a giant "Newbury Comics" billboard at the base of the mountain to help sell that the film takes place in New England. It is also a reference to Adam Green's first film Hatchet (2006) which featured the comic/DVD/music store's "tooth face" logo on lead actor 'Joel David Moore''s T-shirt.
Adam Green uses much of the same key crew positions in every project he does and chooses his projects based on whether or not he can work with his friends. The man on the "Missing" poster in the lodge is Green's usual camera operator BJ McDonnell who couldn't shoot Frozen because he had already booked work on Rob Zombie's Halloween II (2009). The poster is meant to be a shout-out and a dig at BJ for missing the shoot.
Adam Green hit on the idea for the film just prior to going to Canada to start production on the film Grace (2009). As he was only a producer, he could sit in a corner and work on the screenplay. He completed his first draft round about the time that filming wrapped.
The trivia item below may give away important plot points.
The script never revealed the exact way that Dan died as the full horror of the situation was supposed to be reflected in the reactions of his two friends. Nevertheless Kevin Zegers did enact a death scene where he gets savaged by the wolves on the off-chance it would be required for foreign sales.