Tryfan: navigating can provide a challenge. Photo: Neil Cowburn

A mountain rescuer has warned of the difficulties of navigating on a Snowdonia mountain after the rescue of three walkers lasting almost nine hours.

The two men and a woman from Essex strayed on to steep ground after retreating down the North Ridge of Tryfan when they hit wintry conditions.

The trio had to be rescued from the hill’s West Face in a night-time rescue which ended about 3am.

Chris Lloyd of the Ogwen Valley Mountain Rescue Organisation said: “Navigating on Tryfan can be a challenge.

“Maps cannot really represent the topography; GPS readings are sometimes incorrect, possibly due to the shape of the mountain, and the geology seems to lure people to the West Face.”

The team was alerted about 6.20pm yesterday and 20 volunteer team members were involved in the effort to bring the walkers to safety.

Mr Lloyd said the three had come to north Wales the previous day for a few days’ hillwalking.

He said: “They were well equipped and seemed to have a fair degree of experience of walking in the mountains of the UK.

“Unfortunately for them, they had a late start on the North Ridge of Tryfan as one member had left their boots in the holiday cottage. They successfully scrambled up the ridge until they reached the North Tower, where they met the snowline.

“They considered their options and elected to return down the North Ridge. Being in dense cloud and with the onset of dusk, they strayed onto the West Face and down a gully.”

He said their route led to a large drop, so they called 999.

The team used the Sarloc smartphone system which placed them the West Face, between the Milestone Buttress and Notch Gully.

Mr Lloyd said: “A small party was despatched to the popular incident sites of Y Gully and Notch Gully. A second party checked the remainder of the West Face, climbing on to the summit.

“It was evident by the relatively fresh snow cover, that no-one had been on the summits today.

“A third party came up the North Ridge and eventually made voice contact. They were able to traverse in and recover the party of three to the top of the gully.

“They were then walked down the North Ridge arriving at Oggie Base at about 1am

“Here, to the warmth of a glowing wood-burner, they enjoyed hot tea and a bowl or two of chilli before divulging their epic to the team leader.”

The North Ridge is rated at Grade One for a summer scramble, but presents difficulties for many groups in poor visibility and is a favourite call-out spot for the Ogwen Valley rescue team.