In fact, the grandson was not lost — just overdue — while his grandfather had to be winched out by the Roa Mining West Coast Rescue Helicopter as darkness fell.
Senior Sergeant Mark Kirkwood, of Greymouth, said they were notified earlier on Monday that a middle-aged man was overdue in the Cedar Flat area of the Styx River.
"Later we found out that a 78-year-old male, who was the grandfather, had gone into the area where the overdue male was believed to be," he said.
The first man walked out unscathed, but about 7pm on Monday police received a 111 call that the man's grandfather was "cold, lost and didn't know where he was". He also had medical issues.
With darkness fast approaching, police called in the rescue helicopter to uplift him. As the older man did not take an emergency locator beacon with him, they triangulated his location through his cellphone.
Mr Kirkwood said the grandfather was totally unprepared and put himself in grave danger.
He was returned to his car, in the Cedar Flat carpark, and was given a medical check.
"We gave some prevention advice to him and his grandson about leaving good intentions and being well equipped."
Police had spoken to the middle-aged man previously after another incident last December and so were not overly concerned with the initial report that he was overdue.
Mr Kirkwood also noted it was the job of Search and Rescue to find someone who had gone missing.
"Don't go into a search area without asking ... [it] can interfere with a search. A SAR dog is often the first unit we put in."
The Styx rescue was the rescue helicopter's only callout yesterday, leaving Greymouth at 7.30pm and returning at 10.39pm.
