California teen dies after going swimming in Madera County lake

A California teenager was found dead after going swimming in a lake during a hike earlier this month, authorities said.

The Madera County Sheriff's office said in a statement Thursday that it had received a call at around 8 p.m. local time (11 p.m. ET) on Aug. 10 that the 19-year-old had gone missing from his hiking party near Thousand Island Lake.

The teen had been hiking with a large group, which included his father, before going for a swim alone to one of the islands on the lake at around 12 p.m. that day, the sheriff's office said. He was last seen ashore from a distance by his party, it said.

The group that reported him missing later called back to say they had located the 19-year-old and needed immediate medical assistance.

"Due to the urgent nature of the incident, a request was placed with the Governor’s Office of Emergency Services for a military helicopter to respond," the sheriff's office said. Naval Air Station Lemoore accepted the mission and flew out to the location, it said.

When the helicopter arrived, however, responders learned that the young man had died.

NAS Lemoore transported the victim and his father to Fresno Yosemite International Airport, where they were met by Fresno Airport Police and Sheriff’s Office Staff, authorities said.

“On behalf of the Madera County Sheriff’s Office, I extend our sincere condolences to the family and friends of the young man during this tragic time," Sheriff Tyson Pogue said in a statement. "Incidents like this are truly heartbreaking, and some of the hardest calls we conduct as first responders."

The sheriff's office urged those engaging in recreational activities outdoors to exercise caution when swimming in high-country alpine lakes.

"Our high-country alpine lakes are still extremely cold even if the valley floor sees 100-degree days," it said. "At Thousand Island Lake, the overnight lows are in the low 40s at night, and the lake itself is fed by glaciers from Mount Ritter and Mount Banner, the peaks of which peaks are -/+ 12,000 feet in elevation. Even in the warmer months, the water is extremely cold."

CORRECTION (Oct. 11, 2022, 12:55 p.m. ET): A previous version of this article misidentified a lake in a photograph. The image was of Nydiver Lakes, not Thousand Island Lake. The photo has been updated to show Thousand Island Lake.

This article was originally published on NBCNews.com