An RAF Sea King helicopter was scrambled on Wednesday in a bid to rescue a mother and son stranded at more than 3,000ft up Mount Snowdon.
The Sea King flew out from Valley, Anglesey, after the pair were spotted by a walker above Clogwyn Coch.
Llanberis Mountain Rescue Team was also alerted at about 9.35am and 12 volunteer members went to their aid.
A team spokesperson told Grough: "The mother and son left Pen y Pass intending to go to Snowdon's summit via Pyg Track.
"They encountered snow and ice from the intersection of the Pyg Track and the Miners' Track but continued to the summit of Snowdon despite slipping and sliding.
"They decided to descend via the Llanberis Path but quickly became disorientated by wind and cold and felt unable to go on.
"A passing walker who was properly equipped for the conditions stopped to help them and called for assistance from the mountain rescue team."
The spokesman added that both mother and son became hypothermic, and that conditions were "truly awful" with winds of more than 70mph and snow and ice underfoot.
The Sea King search and rescue helicopter from RAF Valley flew to the site but could not reach the pair because of low cloud, according to the Daily Mail.
The pair were then roped to safety by team members then airlifted by the Sea King to Ysbyty Gwynedd in Bangor.
The incident has prompted experts to remind walkers to be properly equipped and have adequate clothing for the 3,560ft mountain, including ice-axe and crampons, as well as food and warm drinks.
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