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Read a specific slope from topographic contours
Contour lines encode slope steepness, direction, and specific landforms if you know how to read them.
Step-by-step
Check the map's contour interval (usually 20, 40, or 100 feet) — every line represents that much elevation change.
Close-packed lines mean steep terrain; widely spaced lines mean gentle terrain.
V-shapes pointing uphill are drainages and streams; V-shapes pointing downhill are ridges.
Concentric closed loops mean summits; loops with tick marks pointing inward mean depressions or basins.
Estimate slope steepness: contours a millimeter apart on a 1:24,000 map with 40-foot intervals mean roughly a 45° slope — near the limit of walkable.
Tip: Trace a proposed route with your finger and count contour crossings — every crossing is one contour interval of climb or descent.
Related outdoor skills
Educational reference only. Wilderness conditions change fast — practice in low-stakes settings, take a certified wilderness first-aid course, and confirm regional regulations before you rely on any of these skills in the field.