STILLWATER — Two snowmobilers were treated after crashing on the frozen Stillwater Reservoir in Herkimer County Saturday afternoon, according to the state Department of Environmental Conservation.

The two snowmobilers, a 53-year-old and a 14-year-old, both of Pennsylvania, were crossing the frozen reservoir on their snowmobiles when they encountered a pressure crack in the trail shortly before 4:30 p.m., authorities said. Pressure cracks form on frozen bodies of water, move without notice and are difficult to see, officials stated.

The 53-year-old suffered a head injury and could not remember the crash, authorities said. They also had abdominal pain and a significant hand injury. The 14-year-old had difficulty breathing and was suffering from chest pain. Authorities said they managed to get to the nearby Stillwater Restaurant, where they were met by state forest rangers and rescue personnel.

The teenager was air-lifted by Mercy Flight helicopter to a nearby hospital, and the 53-year-old was taken by ambulance, authorities stated.