MADERA COUNTY, Calif. (KSEE/KGPE) – A 19-year-old from Los Angeles County has died after swimming at Thousand Island Lake in Madera County.

On Aug. 10 at around 8:00 p.m., deputies say they received a call reporting a teenager who had been missing from his hiking group near the lake in eastern Madera County. The missing person was reported as a 19-year-old man from Los Angeles County who was hiking as part of a large group of people and had been missing for approximately eight hours when the call was made.

The official report says he was seen around noon that day swimming alone to one of the islands in the lake and was last seen ashore from a distance by his group.

While the Search and Rescue teams were coordinating the mission, the group of people reported that they located the person and needed immediate medical assistance. officials say.

Due to the urgency of the incident, a request was placed with the Governor’s Office of Emergency Services for a military helicopter to respond. NAS Lemoore accepted the mission and responded to the location for medical assistance, deputies say.

When the helicopter got to the scene the teen had passed away. Then the crew at NAS Lemoore was able to transport the victim and his father (who was hiking with him) to Fresno Yosemite Airport to meet authorities.

Authorities warn those to recreate outdoors that lakes can be extremely cold; at Thousand Islands Lake, the overnight temperatures can get to the low 40s.