CALIFORNIA—On Saturday, September 5, Benjamin Whittier, 20, was hiking at Joshua Tree National Park, when he was discovered to be unresponsive by his hiking mate in the Turkey Flats area. On Sunday, September 6, Whittier was pronounced dead by the Riverside Country Coroner.

Searchers found Whittier at 11:30 p.m. on Saturday near the base of Pinto Mountain. Staff at  Joshua Tree National Park were not able to save him by administrating CPR.

“The hiker’s body was airlifted by Riverside County Sheriff’s Department. Efforts were aided by Riverside County Fire, Joshua Tree Search and Rescue (JOSAR), and American Medical Response. Temperatures in the area were estimated to have reached approximately 120 degrees,” reads a statement from the National Park Service.

The Riverside County Sheriff’s Department is still investigating the case. Joshua Tree National Park recommends hikers to drink enough water and shift their activities in the early morning to be vigilant in extreme heat during the day.