Widely considered the founding father of Scottish mountaineering, Harold Raeburn's achievements in the Edwardian era were as impressive as those of WH Murray, Robin Smith, Tom Patey, Dougal Haston, Jimmy Marshall or Hamish MacInnes in their respective periods. We might even think of these great climbers as standing on Raeburn's shoulders.

Green Gully (IV,3) on Ben Nevis in April 1906, where he cut steps up near-vertical ice with a single 116cm-long ice axe, was almost certainly the hardest ice climb in the world at the time and wasn't superseded in difficulty in Scotland for nearly 30 years, while Raeburn's Route (IV,4) on Stob Coire nan Lochan and Crowberry Gully (IV,4) on Buachaille Etive Mòr remain two of the most sought-after winter lines today.

But Raeburn's finest achievement was perhaps his 1920 winter ascent of Observatory Ridge (V 4), which retains its reputation as one of the longest and most serious mountaineering routes on the Ben. In the following extract from The Steps of a Giant, published by the Scottish Mountaineering Press, author Peter J Biggar recounts this remarkable first ascent:

On Tuesday, 6 April, Frank Goggs, Editor of the SMCJ, and Arthur Mounsey, with whom Raeburn had also climbed before, joined Harold at Achintee for, so far as we know, his last time on Ben Nevis. Goggs begins his article on the first winter ascent of Observatory Ridge[1] on an elegiac note, mentioning that in 1914 he had walked up the Ben with Harry Walker, who had subsequently died in the War. For Goggs, the Ben had been 'a mind picture, symbolising beauty and peace' during the War, and now that he can visit the mountain again, he feels 'sanctified by the memory of many who can no longer accompany us in the flesh'.

Of Walker, he says: 'Being alone, our conversation was more intimate and personal than usual, and under such conditions you get to know a man in a way that you rarely, if ever, do among bricks and mortar.' How true, and Ling and Goggs must have known Raeburn as well as anyone, for they—particularly Ling—had often been alone with him. It would have been fitting if Ling, too, had been in the party that day, but it didn't work out like that.

Remarking on Raeburn's fitness, Goggs says, 'If you can keep close to Raeburn as he skims along and down the slope, now on turf, now on scree, and now on boulders, with the perfect balance of the born hill man, you are in good training.'

They had a meal after the Douglas Boulder and then wondered what to do. Raeburn thought 'most routes would go'. Only he had climbed Observatory Ridge, in more or less summer conditions. The Journal Editor was in no doubt that this would be the first winter ascent. Decision made. They roped up, Raeburn leading, followed by Goggs then Mounsey. They gave Raeburn 'a generous share of the 100ft rope'. One supposes that amounted to 50–60 feet; it can't have been much more and meant that most of the time the second pair probably climbed simultaneously.

The party made a good start on the first 200ft, 'sound hitches, good standing room, the rocks reasonably broken up, and the demand on the muscles not excessive'. After this pleasant introduction, they came to 'a big slabby face', which at first they thought impregnable. Round the corner to the right was no better, so 'Raeburn examined the slabs more carefully and suddenly exclaimed, "I have it."' Goggs comments on the reliability of Raeburn's memory, and he describes the pitch:

[Y]ou clamber up a slight recess on the right, then when you can get no further and feel uncomfortable, you see a narrow ledge on your left, but out of reach; however, with the aid of a niche for the toe of your boot, and not much more than a balancing hand on the smooth rock face above, you manage to get your knees on the ledge.

It is indeed an awkward move. Goggs, with his usual self-deprecating humour, describes his eventual success, 'How I did it I frankly cannot say, and it really does not matter two straws … Mounsey … had watched my performance and had taken note how not to do it.' He came up 'in fine style'. But, Goggs adds, 'I had my revenge later'. On a more serious note, Goggs gives a good impression of the exposure: 'Looking down one never saw more than two slippery ledges at a time … Looking up, steep frowning rocks were succeeded by steep snowslopes which lost themselves in cloudland.'

Raeburn agreed to pause for food, but such was the gradient that they could find nowhere to sit or stand in comfort and had to go on. Looking for a place to stop, they had deviated from the crest. Raeburn climbed a short gully back to the ridge, but Goggs had such difficulty following that he had to use Mounsey's shoulder, and then, of course, Mounsey, who was a heavy man, had to come up on a tight rope. '… there was rather a struggling and a kicking before the third man's head appeared on the ridge'. Goggs's revenge.

It had been snowing for some time, and 'Rocks … which Raeburn said were easy in summer, now proved the reverse.' The direct way, over glazed rock, seemed impossible, so, as one does on a difficult and perplexing route, they manoeuvred about looking for an easier way. Making a short descent, they found a good hitch—'a curious spike of rock 15 inches long'—and Raeburn's rope was 'promptly drawn round it'. He tried to the left but soon came back and searched elsewhere. Looking up, Goggs and Mounsey wondered if the cornice would be surmountable, but retreat would have been desperate. Raeburn was unconcerned about the cornice, but he still couldn't find the way ahead. He tried a band of snow running down to a gully, but there was no ledge beneath it. Saying: 'It's got to go,' he disappeared left again, and for the next 15 minutes they saw nothing of him, but heard and saw snow and ice hurtling down. They could only wait and hope. Eventually the rope went out more quickly, 'and a halloo from our leader announced his conquest of the difficulty'. Goggs says that when he followed, he found the pitch comparatively easy as the second, but that 'the route, a clamber over … rounded and holdless rock, was very difficult for the leader'.

They now took to the gully on the left (Zero Gully). It was high-angled, and Raeburn ran out 'length after length of rope'. Moving one at a time, they made slower progress, often without adequate belays of any kind because rock could not be reached, or because the snow was too thin or hard to embed an axe into. Spindrift frequently swept down, but gradually the weather improved. Goggs marked their progress by noting that they were slowly climbing above the height of Càrn Mòr Dearg and could see the Aonachs beyond it. He also comments on the strange, 'almost weird' absence of life: no birds, no insects. In good romantic fashion he quotes Byron's lines[2] about the Alps seen as 'The palaces of Nature …' Scottish palaces were all around.

On a more mundane level, Goggs feared the onset of cramp: '... the steps were … small, the angle steep, the ice-axe could rarely be depended on to give a satisfying sense of security'. While Raeburn ran out the notional 50ft, Goggs and Mounsey presumably first had to move together and then remain on small stances Raeburn had cut from the steep ice or névé. They had to wait until Raeburn could protect them with some kind of hitch, but there were frequent calls to follow because Raeburn could find none. On these occasions, when all three moved together, a slip by any of them could have had fatal consequences.

At last Raeburn could assure them that 'victory was at hand'. A minor icefall between rocks had 'steps cut aslant the ice', and after another 20ft of névé Raeburn landed on 'snow-covered flat rocks'. Goggs says: 'At the icefall a few rocks jutted out on the right, and I remember the feeling of security and satisfaction there was in gripping a rough rock surface.' Even then they were not quite at the top but in a gently angled snow bay fringed by a moderate cornice 'vulnerable at several points'. Half a dozen steps up the cornice 'landed us on the summit plateau'. Right on cue, 'the sun, which had been threatening to break through the scurrying clouds, bathed us in light …'

Congratulating Raeburn on his magnificent leading, they celebrated with acid drops, brandy balls, a jam piece and chocolate. The climb had taken just five-and-three-quarter hours. Back at the Alexandra Hotel, they delighted in telling Harry MacRobert that his newly published guide to Ben Nevis was already out of date.

With the first winter ascent of Observatory Ridge on Tuesday, 6 April 1920, Raeburn's mountaineering career in Scotland comes to a glorious but abrupt end. He had been climbing new routes all over the Highlands for some 25 years, but now his name all but vanishes from the pages of the Journal until his old friend Willie Ling writes his obituary in 1926 and Sandy Mackay belatedly contributes his article on climbing the Barrel Buttress on Quinag in 1928. So far as Scotland is concerned, 'The rest is silence.'

The ascent of Observatory Ridge in full winter condition was one of Harold's finest achievements: its accomplishment a reward for years of persistent effort. Raeburn had been the first ascensionist in summer; he had climbed the route several times since then and descended it at least once; he knew it well, but of course winter conditions change everything. We need constantly to remind ourselves that Harold and his companions had little protection except the dubious kind provided by hitching the rope behind some projection, or the use of an ice-axe belay in snow that was often too shallow or too hard. They had nailed boots, but no crampons. Most of the time, they were moving together as a rope of three on 100ft of half-frozen hemp line of doubtful strength. They depended on their skill—particularly Raeburn's—experience and fitness to find the way, clear holds on the rock and cut steps in the ice. We should not forget that Goggs and Mounsey were also both very experienced mountaineers and that either of them could have taken over the lead in an emergency. But neither had climbed the route before, whereas Harold knew the lie of the land and was an acknowledged master. On virtually any route in the previous 25 years, he had been expected to lead. The rule was "the leader must not fall", and he never did.

Nowadays Observatory Ridge is regarded by most experts as the hardest of the three great Nevis ridges in winter. It has been justly said that while modern long ropes and abundant belaying devices make the route safer, the advent of front-point climbing with crampons and the use of two axes has not made it any easier. The Ridge is now graded between IV,4 and V,4; a realistic grade in most conditions is probably IV,5 because of the technical difficulty of the harder pitches. How many parties of three, one wonders, better Raeburn's time of five-and-three-quarter hours? Most parties of two take longer.

Like the ascents of Green Gully, Crowberry Gully and many other fine if less famous routes, Raeburn's ascent of Observatory Ridge in winter has only come to be appreciated in modern times. As with his traverse of the Meije the previous year and his forthcoming expedition to Kangchenjunga in the same year, it provides sound evidence that his selection as Climbing Leader of the 1921 reconnaissance expedition to Everest was thoroughly justified.

The Steps of a Giant is available to pre-order now from the Scottish Mountaineering Press. There will be a launch event at the Fort William Mountain Festival on the 17 February where author Peter J Biggar and editor Deziree Wilson will be signing copies of the book.

[1]. SMCJ 15, 90, 1920: 310-318.

[2]. From, appropriately, Childe Harolde.