San Diego County responders were unable to save a 19-year-old woman found unconscious with signs of possible heat stroke on a hiking trail near Cedar Creek Falls on Monday.
Deputies say they've responded to a number of distress calls from hikers in recent days as Southern California sweats out the summer's first heat wave.
Elevated temperatures and increased humidity will create potentially hazardous conditions through Thursday, according to the National Weather Service. The heaviest heat is expected to hit lower desert areas with highs nearing 120 degrees.
Excessive Heat Warnings and Advisories remain in effect for Los Angeles/Oxnard and other portions of Southern California.