Andy Pascall, 23, of Marlow, and Andrew Hindley, also 23, from Bourne End, both in Buckinghamshire, were standing at the top of the 13,600ft Jungfrau mountain near Interlaken when the ground crumbled beneath them on Sunday afternoon.
Mr Hindley died in the fall, but Mr Pascall found his way to a mountain hut at about 1am on Monday and managed to raise the alarm.
He was taken to Interlaken Hospital suffering from a broken arm and injured knees.
Mr Pascall and Mr Hindley had been among a four-man party from the Vulcan Venture Scout unit in Marlow. The other two, Martin Kolaszynski, 21, and Craig Fines- Allin, 20, were unable to raise the alarm because of deteriorating weather conditions, and were airlifted to safety after Mr Pascall alerted rescue services.
Derek Walker, general secretary of the British Mountaineering Council, said the two men may have fallen through a snow cornice.
'Sometimes the snow gets windblown into a position where it's frozen and stuck to the side of a ridge, but if you stand on it you go through.'
But he said it was also possible they were roped together in pairs, and that one had slipped and pulled his companion down with him.
He said Mr Pascall was lucky to survive the fall, but similar things did happen. 'People can take very long falls down snow slopes and survive, as long as the landing is OK and they don't go over ice cliffs or land in a crevasse.'
Mr Hindley's father, Alan, said yesterday: 'Our son was an experienced mountaineer who loved the outdoor life. He had just gained a first-class masters degree in electronic engineering at Loughborough University and was looking forward to getting back to helping other members of the Venture unit experience the pleasures of the outdoor world he loved so much.'
The party of friends had strong links with the Scout Association and were all Queen's Scouts - the top award. They were all experienced in outdoor activities.
The Chief Scout, W Garth Morrison, said: 'Very occasionally, and despite every precaution, an incident such as this will regrettably occur. When it does it highlights our awareness of the need for continuing vigilance and to monitor all the training we offer to young people and adults.'
He added: 'Our prayers and thoughts are with the families and friends of everyone concerned.'