Staying alive above the snow line: The higher you climb, the more pitfalls you need to avoid, says

ABOUT the time last Sunday afternoon when Jacqueline Greaves's two companions plunged through a lip of snow on Derry Cairngorm, precipitating a survival drama, I was 25 miles to the south on Schiehallion, a peak of a similiar height.

Mountain weather is notoriously fickle and localised, but conditions there were probably not much different. Along the summit ridge we had to lean at an absurd angle against a gale- force east wind. Visibility was often down to a few metres and finding and confirming the summit required map, compass and altimeter.

Yet, very probably like Mrs Greaves and her friends, we had set out that morning in sunshine. The glens could not have looked lovelier, the low-angled sun picking up the warm russets and browns of dead bracken and dormant larches. We hit the snow line at about the 500m contour. Other parties were out and at this point were unslinging ice axes from their packs and strapping on crampons - spikes that are attached to boot soles and bite into the snow and ice for security. We were making the ascent on skis but took similar precautions.

At that point it seemed a good day for winter mountaineering. We would have enjoyed it more without the biting easterly which scoured the ridge. But it was not unexpected, and anyone who ventures on to the Scottish hills should go prepared for foul weather higher up. Mrs Greaves was - and thus she is alive today.

Derry Cairngorm rises to 1,155m, north-west of Braemar. As part of the great Cairngorm massif with its semi-arctic plateau, Derry Cairngorm's slopes would generally hold more snow than the isolated Schiehallion (1,083m). The walk-in up Glen Lui, past stands of ancient Caledonian pines, would have made an uplifting start to the mountain day.

It went wrong, according to reports, above Coire an Lochain Uaine, a craggy, steep-sided bay on the east side of the mountain. The edge of the corrie would be a hazardous place in poor visibility, probably with a lip of wind- driven snow, or cornice, curled over the edge. Step here and you could easily break through the snow and into the void below. It is a common cause of accidents in Scotland because the conditions often mean that cornices cannot be seen.

In the white-out across the summits in recent days, driving snow and cloud will have merged so totally with the surface that climbers would not know if they were ascending or descending. Cliff edges would become invisible. Map, compass, altimeter and, most importantly, confidence in using them, are then life-savers. It is hopeless putting theory into practice for the first time if a 70mph blizzard is tearing the map from your hands and blinding your eyes.

Mrs Greaves's companions both went through a cornice. Bruce Nutter fell about 50m before arresting his slide with an ice axe. Here is another mark of experience. Ice-axe braking - forcing the pick of the tool into the slope - is seldom as easy as it looks in the manuals. Mr Nutter's fellow teacher, David Cawley, slid a good deal further but was similarly unhurt.

The two men could not find each other as they made their way separately off the mountain to raise the alarm. Such were the wild conditions that Mrs Greaves was now alone as she began her two-day fight for survival. With wind- chill, the effective temperature dropped as low as minus 26C.

No amount of warm clothing would have been sufficient, and the 53-year- old school secretary from Lancashire clearly knew this. Modern fabrics allow for thermal-efficient lightweight layering under waterproof shells. But there are limits. Mrs Greaves had to get out of the wind if she was to spend a night on the mountain.

According to a doctor who spoke to her as she recovered in hospital, Mrs Greaves spent the first night in a gully into which she had fallen and the second in a snow hole. She had recently been on a winter skills course which would include snow-holing. What she learnt on that course was undoubtedly crucial to her survival. Indeed, some of the 70-strong searchers also had to dig themselves shelters from the wind.

There are mountaineers who prefer a snow shelter to a tent in the greater ranges of the world, where a good depth of snow is guaranteed and time can be taken crafting sleeping bag-size platforms. Snow holes are windproof and snow is such a poor conductor of heat that the interior is quickly warmed by the occupants. But snow holes in Scotland are usually emergency shelters, hastily dug with an ice axe in a bank of snow.

Mrs Greaves may have been carrying other survival gear. Lots of winter hill-walkers and climbers carry a body- sized bivvy bag, maybe an expensive one made of Gore-tex, or just a bin- liner. Most days it is just dead weight, but if used to spend the night it is a godsend.

On days like last Sunday, climbers quite likely carry snack lunches up the hill and then do not eat them because it is too cold to linger on top. So food is there in an emergency. Others take specific precautions. Getting grubby at the bottom of the rucksack, along with some old sticking plasters, there may be a slab of Kendal Mint Cake - too sweet to eat normally, but nectar when really needed. Mrs Greaves was prepared right down to a whistle, though in the high winds searchers who passed nearby on the first night did not hear her distress calls.

But there is a balance to be struck. Speed is also a life-saver in the mountains. The weight of too much survival gear - extra food and clothing and perhaps a heavy spare battery - can slow you down. Carry too much and spending the night out on the mountains becomes an increasing possibility.

Part of the ultimately indefinable attraction of mountaineering is the importance taken on by seemingly mundane decisions of what to pack, or which route to take up which mountain given the weather conditions and your own experience. These are real decisions. Get them right and there is the satisfaction of a job finely executed.

Get them wrong and, well . . . on Monday the Government released figures showing that Scottish rescue services had responded to 79 incidents involving climbers and hill-walkers since 1 October 1993, and 21 people had died. In England and Wales there had been 172 incidents, including 17 deaths.

Happily, Mrs Greaves and her friends have been added only to the 'incidents' column.

(Photograph omitted)