Authorities are investigating a man's death along a popular mountain-biking trail in Washington County.

Sheriff's deputies said it happened in the Little Creek area, where Joseph Manning, 40, of Avendale, Pa., had been mountain biking with friends when he became separated from them.

"He was later found by his friends near a pool of water. His friends started CPR on him until assistance arrived," Washington County Sheriff's Chief Deputy Rob Tersigni said Tuesday. "Medical personnel took over but were unable to revive him."

Manning's body has been sent to the state medical examiner for an autopsy, but Tersigni said there were no obvious signs of foul play. Temperatures in the area were nearly 100 degrees, prompting the Washington County Sheriff's Office to warn anyone hiking or biking in Utah's red-rock country to be prepared.

"With any type of activity, your body can overheat quickly, causing you to go into distress," Tersigni said.

— Ben Winslow