A 51-year-old Guelph man has been reported missing in Joshua Tree National Park in California.

Paul Miller told his wife he was going for a hike on the morning of July 13, leaving his cell phone behind.

He left at around 9 a.m. local time, and was only supposed to be gone a couple of hours.

He hasn't been seen since.

His car has been found at the parking lot of 49 Palms Oasis trailhead.

Guelph Mayor Cam Guthrie has known the man for two decades through Lakeside Church.

“We are just praying he comes home safely,” Guthrie said.

As many as 90 ground searchers have been active looking for Miller since he went missing.

Temperatures have been extremely high in the park, increasing the urgency to find him.

Teams have been searching for him from the air and ground.

Heat seeking equipment has been unreliable due to retained heat in the park.

Three searchers have been treated for heat exhaustion.