Officials say it happened shortly before 1 pm on the Madera County side of the lake.
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Armando Juarez's stepfather called for help and said the 15-year-old went out in the water but hadn't been seen for quite some time.
The teen was located about an hour later by a state park lifeguard.
CPR was performed and Armando was taken to the hospital where he was later pronounced dead.
NOTE: An earlier version of this story said Armando's age was 13. The Madera County Sheriff's Office later said his age was 15.