FOUR killed in an Aonach Mor avalanche brings poignantly home the intractable nature of nature. The fact that those who died were only on the threshold of a sport that has given so many a lifetime's fulfilment merely heightens the tragedy. All who climb are subject to what is often lightly called objective danger such as avalanche, stonefall, crevasse, lightning, blizzard etc. And what the general public may consider an unacceptable risk they calmly anticipate themselves every time they plan a lengthy winter drive.

My youngest son, Graham, walked unscathed from a series of potentially fatal car crashes of which he was not the author. My wife and I, though shaken by events, marvelled at his survival potential. Often in the event of objective hazard that's what coming back intact amounts to. No degree of awareness is sure to save your neck, a mountain verity too obviously illuminated by the death of Dougal Haston, for instance, in a Leysin avalanche.

Not only Scotland's leading mountaineer of his era but rated by Messner at one stage among the world's elite, Dougal was one for pushing the limits. And his death came, over-stretching the potential, doing what he loved. Reinhold Messner himself has stated that his own great forte is not climbing but surviving.

Going to the brink, climbing's cutting edge, has brought the sport to the level of achievement that might have seemed fantasy only a couple of decades ago. And at what cost in human terms. Yet Max Stirner reminds us:

''The more we know of something the smaller appear those obstacles that at first seemed unsurmountable. And what is all our wisdom, all our wiliness, boldness, our spirit? What else but what we sense and know?''

For all his vast experience and wiliness, Haston apparently succumbed to a simple error of judgement. The lure of the mountains was too great to ignore though the local avalanche risk for skiing on the day was reported to be high. The Scot who first mastered Nevis then the Matterhorn, the Eiger, Annapurna and Everest direct, went down in an otherwise unremarkable snow slide.

Some think that men or women of Dougal's calibre are virtually fearless and almost certain to hit the buffers, given enough line. If you'll excuse another plagiarism, the great Yannick Seigneur, who knew a thing or three, wrote:

''On a mountain, a man meets fear. The more he understands about what he is doing, the more fear he will experience. Because the abler he is then to recognise danger.''

Few have mastered the dimension of anxiety handled over the years by Messner, now 54, whose conquest of the planet's 14 highest summits (two solo, and never with bottled oxygen) has elevated him to icon status. Yet he gladly acknowledges his debt to those who had gone high and very hard before.

One mountaineer more than any other embodied that fearful but wily, obsessive and fully committed, cutting-edge spirit. The Austrian, Hermann Buhl, went alone in 1953 for the 8000m crest of Nanga Parbat (repeated 25 years later by Reinhold) in the Karakoram, and survived.

A member of a major siege expedition much like Britain's on Everest that momentous year, Buhl broke the mould by pressing on alone. On the steep summit ridge, without artificial air, Hermann was heaving four to five breaths per step. His 41 hours alone included an arctic night out above 25,000ft standing upright, half-awake, on a precarious stance one of the most harrowing outings ever documented. Ever on his mind, of course, was the knowledge that 31 climbers and porters had already died attempting this very ascent of Nanga Parbat.

His epic climb and descent to Camp V appeared to age him, he claimed, nearly 30 years, and cost him a couple of toes from frostbite. But he had uncovered the human potential at altitude that was to inspire Messner and others to come. Buhl's life in the mountains remains a remarkable inspiration and his autobiography, Nanga Parbat Pilgrimage is newly reprinted in Hugh Merrick's brilliant translation.

The power to raise the game for those yet to come in any world competitive sphere, whether - music, art, sport, business or anything else is no easy affair. Buhl, born in Innsbruck in 1924, took to the mountains of his Austrian ski resort from the gun. From a poor family and later making only an average living there as a shop salesman, Hermann struggled to afford his escapes to the rock and ice of the Easter, and duly Western Alps.

Yet his drive was phenomenal. The great north faces fell before his obsessive intellect and energy. His survival at times was something extraordinary. He scared off his contemporaries. ''My companions have never been able to get undiluted pleasure from being with me,'' he wrote. ''They never could have; I admit it freely. Even when there was a storm outside, or a blizzard, or the monotony of heavy rain blanketed a disconsolate world, it was still fine for me.''

Hermann once cycled 100 miles through twisting, undulating valleys and over a major Alpine pass to make the first solo ascent of the formidable north east wall of Piz Radile, in the Italian Dolomites. Feted briefly by the locals for ''La Prima solo'', and without rest he push-biked it back to Innsbruck where, exhausted, he crashed arse over elbow in the river.

His escapes from Alpine and Himalayan avalanches, a crevasse accident, and the White Spider exits of the Eigerwand, curdle the blood.