The accident took place on Tuesday evening at Clogwyn Y Grochan in the Llanberis Pass.
Mr Evans, aged 54, was a member of the Ogwen Valley Mountain Rescue Team. He was out enjoying a social climb with his partner Lynne when the accident happened. They had just climbed the route Nea, when John fell a considerable distance whilst descending a gully.
Fellow rescue team members rushed to his aid but were unable to save his life.
North Wales police are currently working with the Mountain Rescue Team to establish the exact cause of the accident.
Mr Evans lived in Capel Curig and was an accomplished and experienced climber, having spent time as a mountain guide in Alaska as well as being a knowledgeable instructor in technical rescue rope work.