Some of his regular mountaineering partners in Norway were William Cecil Slingsby, Howard Priestman and Norwegians Kristian Tandberg and George Paus.
Living under Edinburgh's Salisbury Crags and possessing a wiry, athletic build he soon adapted to the vertical world of rock and ice.
As to his character, he very obviously possessed the necessary determination and drive of any ambitious and hard mountaineer; Lord Mackay provided a good description of Raeburn, writing that he was "... physically and mentally hard as nails, trained by solitary sea-cliff climbing after birds' haunts, he was certain, unyielding and concise in every movement, both mental and physical."
Mackay went on to remark that Raeburn had a capacity of grip that was astonishing: "He was possessed of strong muscular fingers that could press firmly and in a straight downward contact upon the very smallest hold.
"[1] Raeburn remained a bachelor all his life but he climbed with both men and women, including his sister Ruth, herself an expert climber, and Jane Inglis Clark, a founder of the Scottish Ladies Mountaineering Club.
solo in June 1902, his outstanding eponymous Arete (Severe) two days later on North-East Buttress with William and Jane Inglis Clark, and the first winter ascent of Green Gully (IV,4) in 1906.
The latter ascent, with a Swiss alpinist called Eberhard Phildius, was barely recognised in a later guidebook, as he had not climbed the rocks of the Comb on the left, but had instead followed snow and ice in the gully.
In Easter 1920, during the SMC Meet at Fort William, Raeburn made what perhaps his finest winter ascent in Scotland – the first of Observatory Ridge on Ben Nevis.
With fellow members Mounsey and Goggs, and using a 100 ft rope, the three finished the route in just under six hours, with one long ice axe each and no crampons.
Raeburn's book, Mountaineering Art was in manuscript when World War I began, and long, hard hours in an aeroplane factory for the next six years stopped all climbing.
His diaries on the sea birds of the Shetland Islands and other species are lodged in the archives of the Department of Natural Sciences, National Museums Scotland.
Raeburn's account of the 1906 winter ascent of Green Gully with the Swiss climber Eberhard Phildius is reprinted in Wilson, K., Alcock, D. and Barry, J., Cold Climbs, Diadem Press, 1983.
A fictional short story by Ken Crocket describing Raeburn's first climb as a young schoolboy was published in the Scottish Mountaineering Club Journal as "Raeburn's First Climb" (1988) (reprinted as "October Day" in One Step in the Clouds, Diadem Press, 1990, compiled by Audrey Salkeld and Rosie Smith, ISBN 0-906371-92-9).