Search teams at Joshua Tree National Park in California are scaling down their efforts for missing Guelph hiker Paul Miller.
The 51-year-old has been missing since Friday and over the past five days, ground teams, canine crews, a helicopter crew and ATV searchers have been out looking for the man.
At one point over 90 people were on the ground looking for him.
Public Information Officer at the park, George Land, tells 570 NEWS they have found no trace of Miller, coming up on a "complete blank wall."
"We have put just about every effort into finding Mr. Miller without success, even any trace, any tracks, the dogs have not had a hit on the trial, nothing cast off in the way of empty water bottles or clothing ... obviously those levels of resources and assets are not sustainable, so resources have been reduced. The incident enters a phase of what we call a 'limited continuous search mode'... during this phase we will continue to search areas of high probability when we have sufficient resources."
He adds it's rare that someone gets lost on the particular trail Miller was hiking on, something that is contributing to the mystery of this case.
The 800,000 acre park has had over 3.1 million visitors this year alone with five other missing person cases. Land says all those people were found successfully and reunited with their families.
On Wednesday, only a couple of people are out looking for Miller, with Land saying another small team will be out on the weekend.
The park is not recommending hiking for anyone at this time since extremely hot temperatures are being recorded in the area.
Over the weekend, temperatures peaked at 43 degrees Celsius.