Legends: Rapidly Rising Terrain

Pilots spend a lot of time preparing for the unexpected?engine problems, freak winds, forced landings. But what happens when the unexpected is literally part of the landscape, say cliffs rising dramatically out of otherwise rolling terrain? That?s where careful reading of sectional charts can help pilots avoid unpleasant surprises. The warning on this chart is clear: ?Caution. Rapidly rising terrain.? In this example from the St. Louis sectional west of Nashville, Tennessee, the terrain in question is a steep-sided plateau protruding sharply above the surrounding hills. The edges of the plateau are marked by what appear to be thicker, darker contour lines with short perpendicular lines extending from them. By looking at these special markings, which are not explained in the chart legend, in combination with the more familiar contour markings, pilots who are unfamiliar with this local topographical oddity can select a safe altitude and avoid an unexpected encounter with a cliff face. n ? Elizabeth A. Tennyson