According to police, the boy and his two brothers hopped a locked fence at the Mt. Olympus resort water park around 10:30 p.m. on Wednesday to sled down an outdoor water slide.
The teen apparently got stuck in the snow about half-way down the slide. When he tried to free himself, he slipped and fell 35 feet to the ground.
Authorities say a paramedic was driving by the water park at the time and hopped the fence with a defibrillator. Officials tried to resuscitate the teen but he died from his injuries.
Lake Delton police say the family was visiting Wisconsin to experience snow for the first time.
Officials said the park, which is closed for the season, had locks on all of its gates.
No charges are being issued.