The Shining

Jack Torrance (Jack Nicholson) arrives at the mountain-isolated Overlook Hotel, which is 25 miles from the closest town, to interview for the position of winter caretaker. Once hired, Jack plans to use the hotel's solitude to write. The hotel, built on the site of a Native American burial ground, becomes snowed-in during the winter; it is closed from October to May. Manager Stuart Ullman (Barry Nelson) warns Jack that a previous caretaker, Charles Grady, developed cabin fever and killed his family and himself. In Boulder, Jack's son, Danny Torrance (Danny Lloyd), has a terrifying premonition about the hotel, viewing a cascade of blood emerging from an elevator door, and then falls into a trance. Jack's wife, Wendy (Shelley Duvall), tells a doctor (Anne Jackson) that Danny has an imaginary friend named Tony, and that Jack has given up drinking because he dislocated Danny's shoulder following a binge.
The family arrives at the hotel on closing day and is given a tour. The chef, Dick Hallorann (Scatman Crothers), surprises Danny by telepathically offering him ice cream. Dick explains to Danny that he and his grandmother shared this telepathic ability, which he calls "shining". Danny asks if there is anything to be afraid of in the hotel, particularly room 237. Hallorann tells Danny that the hotel has a "shine" to it along with many memories, not all of which are good. He also tells Danny to stay away from Room 237.
A month passes; while Jack's writing goes nowhere, Danny and Wendy explore the hotel's hedge maze, and Hallorann goes to Florida. Wendy learns that the phone lines are out due to the heavy snowfall, and Danny has frightening visions. Jack, increasingly frustrated, starts behaving strangely and becomes prone to violent outbursts. Danny's curiosity about room 237 overcomes him when he sees the room's door open. Later, Wendy finds Jack screaming during a nightmare while asleep at his typewriter. After she awakens him, Jack says he dreamed that he killed her and Danny. Danny arrives with a bruise on his neck and traumatized, causing Wendy to accuse Jack of abusing him. Jack wanders into the hotel's Gold Room and meets a ghostly bartender named Lloyd (Joe Turkel). Lloyd serves him bourbon while Jack complains about his marriage. Wendy later tells Jack that Danny told her a "crazy woman in one of the rooms" attempted to strangle him. Jack investigates room 237, encountering the ghost of a dead woman, but tells Wendy that he saw nothing. Wendy and Jack argue over whether Danny should be removed from the hotel and a furious Jack returns to the Gold Room, now filled with ghosts attending a ball. He meets the ghost of Grady (Philip Stone) who tells Jack that he must "correct" his wife and child and that Danny has reached out to Hallorann using his "talent". Meanwhile, Hallorann grows concerned about what's going on at the hotel and flies back to Colorado. Danny starts calling out "redrum" and goes into a trance, referring to himself as "Tony".
While searching for Jack, Wendy discovers he has been typing pages of a repetitive manuscript: "all work and no play makes Jack a dull boy". She begs Jack to leave the hotel with Danny, but he threatens her before she knocks him unconscious with a baseball bat. She drags him into the kitchen and locks him in the pantry, but she and Danny are both trapped at the hotel: Jack has disabled the hotel's two-way radio and snowcat. Later, Jack converses through the pantry door with Grady, who unlocks the door.
Danny writes "REDRUM" on the outside of the bathroom door in the family's living quarters. When Wendy sees the word reversed in the bedroom mirror, the word is revealed to be "MURDER". Jack begins hacking through the quarters' main door with a firefighter's axe. Wendy sends Danny through the bathroom window, but it will not open sufficiently for her to pass. Jack breaks through the bathroom door, shouting "Here's Johnny!", but retreats after Wendy slashes his hand with a butcher's knife. Hearing the engine of the snowcat Hallorann borrowed to reach the hotel, Jack leaves the room. He kills Hallorann with the axe in the lobby and pursues Danny into the hedge maze. Wendy runs through the hotel looking for Danny, encountering ghosts and the cascade of blood Danny envisioned in Boulder. She also finds Hallorann's body lying in the lobby. Danny lays a false trail to mislead Jack, who is following his footprints, before hiding behind a drift. Danny escapes from the maze and reunites with Wendy; they flee in Hallorann's snowcat while Jack, lost in the maze, collapses from exhaustion and freezes to death. In a photograph in the hotel hallway dated July 4, 1921, Jack Torrance smiles amid a crowd of party revelers.

Question: What is the cause of the phone lines being out?
Answer: heavy snowfall