Frostbite by Richelle Mead

Frostbite is a vampire novel written by Richelle Mead. Frostbite is the second novel in the #1 New York Times bestselling series, Vampire Academy. Frostbite continues the story of the main character, Rose Hathaway including her bond with Vasilisa, her budding romance with her instructor Dimitri, and her education in becoming a Guardian.
The story begins with Rose and Dimitri traveling to meet the legendary guardian Arthur Schoenberg for Rose's Qualifier Exam. Once they arrive at the home of the Moroi family he protects, they discover a bloody massacre of the entire family and their guardians, including Arthur. Rose also discovers a silver stake, a magical device which Strigoi cannot touch, meaning the Strigoi must have had human assistance in their attack. The massacre puts the vampire community on high alert. To keep the students at St. Vladimir's Academy safe, a ski trip to a lodge owned by a wealthy Moroi family is required right after Christmas.
During the ski trip, panic sets in when news of another Strigoi attack on a royal Moroi family spreads, where one of the dead was Mia's mother. During her stay at the lodge, Rose meets a Moroi named Adrian Ivashkov, who shows obvious interest in Rose, and later becomes friendly with Lissa after they both discover they are Spirit users. During Adrian's pool party, Mason, his friend Eddie, and Mia begin voicing their opinions about hunting Strigoi... (Summary by Wikipedia)