Trackers are combing part of Joshua Tree National Park in California looking for a Guelph man who went missing.

Paul Miller told his wife he would be hiking for a couple hours on Friday morning but never returned. 

The search for the 51-year-old is in its fifth day and officials say the heat is making it difficult.

A spokesperson for the park says they found Miller’s car with his cell inside at the trailhead.

Several search units, including helicopters and ATVs have been out each day to look for Miller.

The sweltering heat can reach upwards of 37 C in the park during the summer months.