the wind can whip up snow on the ground to produce whiteout conditions for a few metres above the surface, and snowdrifts can build up rapidly in sheltered places. Gravel can be blown through the air, and walking can be impossible. Scottish mountaineer Adam Watson explained how gale conditions can be extremely challenging on the plateau and make it difficult, if not impossible, to walk, see beyond a few feet, breathe and communicate with other party members. On 20 March 1986, a wind speed of () was measured at Cairngorm summit weather station, which in 1971 was the highest wind speed recorded on land in the UK. Trails and buildings in Cairngorms The valleys between the individual plateaux were used as drove roads by cattle drovers, who built rough protective shelters for their arduous journeys. Even today, between Pass of Drumochter and Lecht there are no paved roads over the Speyside–Deeside watershed, and the passes are impossible, even for four-wheel-drive vehicles. The Lairig Ghru pass between Speyside and Deeside is about long and reaches its greatest height at Pools of Dee at , where the water may be frozen over even in midsummer. The route has a total ascent of about between habitation at Coylumbridge in Speyside and Linn of Dee. Towards the end of the 19th century, as droving died out, deer stalking estates were flourishing and so the shelters were developed into bothies to provide improved, though still primitive, accommodation for gamekeepers. In modern times, the bothies have been taken over by the Mountain Bothies Association for use by trekkers and climbers to provide shelter and rough sleeping accommodation. Starting in 1960 an area in the Northern Corries between Aviemore and Cairn Gorm was developed for alpine skiing. A road was constructed to an elevation of in Coire Cas where a ski centre was built and ski lifts and tows were installed, one going up to a new restaurant, the Ptarmigan, at . In good weather it was an easy walk from there to the Cairngorm Plateau. After the Second World War, the Scottish Council for Physical Recreation established Glenmore Lodge, beside Loch Morlich, on the road between Aviemore and the ski centre. In 1959, it moved to a purpose-built centre nearby (later the Scottish Centre for Outdoor Training, which provides training for leadership in mountaineering), and staff were on the spot to help in mountaineering emergencies. In