Compass and Map : Page 240

The map and the ski tour.—A skier makes good use of his ability to visualize terrain by reading a good topographic map, correlating this information with his knowledge of the region and basic ski-mountaineering requirements. The slope can be determined roughly by the spacing of the contours. The height of the slope can be told at a glance. The experienced map reader will recognize which slopes are so long and of such high angle that they will be especially subject to avalanches. The exposure of the slope, readily seen on the map, will suggest what will be the effect of sun upon the snow. The skier may thus be able to plan his trip on north slopes to take advantage of powder snow; in spring he may choose north slopes at certain times of day to take advantage of frozen crust, or south slopes to avoid it. Angle and direction of slope may determine wind exposure, to be avoided in storm, or sought on a hot day. The map will suggest where cornices are formed, and where wind-slab avalanches are most likely; it may tell, indirectly, where a timberline camp may be made, which slopes will be