Why Contours Deserve Your Attention

Contour lines are the most useful thing on a hill map, and the most widely ignored. Most of us glance at them, see a plate of brown spaghetti, and go straight back to the paths. That is a shame, because contours show you the shape of the ground before you set foot on it: where the slope eases, where a path will be a proper pull, and whether that tempting shortcut actually ends at a cliff edge.

Once you can read them, fell navigation stops being about following a line and starts being about understanding a landscape. You will plan better routes, arrive less knackered, and find the quiet corners where the water sits still.

Spacing Is Steepness

On most British hill maps the contour interval is ten metres: every line is a step of ten metres in height. The single most useful rule follows from that. Contours drawn close together mean the ground rises quickly. Contours spread apart mean it rises slowly.

• Wide spacing — gentle ground, easy walking, often boggy on flat, badly drained cols.
• Evenly tight spacing — a steady slog, the sort that has you counting steps.
• Touching or merging lines — very steep ground. If those lines run for any distance, treat it as a crag and plan around it.

Look at the whole slope, not one patch. Uniform spacing from bottom to top means a consistent angle you can plan for. Where the spacing suddenly changes, so does the walking, and that is where the interesting decisions live.

Shapes That Warn You About Crags and Gullies

Where a band of contours bunches tightly mid-slope and then relaxes again, you have a break in the hillside: often a rock band or a steepening that will need hands. Confirm it with the crag symbols, but trust the contours first — symbols get crowded out on busy maps.

Watch for contour lines that kink sharply as they cross a stream. A tight V on a watercourse usually means a gully or a waterfall, and the ground either side will be loose and awkward. These are exactly the places to avoid in descent, especially in cloud or after heavy rain.

Spurs, Ridges and Re-entrants: Natural Handrails

Contours bend into V and U shapes around the folds of a hillside. The rule is worth memorising:

• A V pointing uphill marks a re-entrant — a valley or gully cutting into the slope.
• A V pointing downhill marks a spur or nose of ground pushing out from the hill.

These features are handrails. Walking a ridge or following a spur means your position is constrained by the ground itself, so errors stay small. In thick cloud, count the spurs as you descend and you can often place yourself to within a few dozen metres. Spurs also make good attack points: aim deliberately to one side of your target and walk onto it, rather than trying to hit it dead on.

Counting Contours and Judging Effort

Because each line is a fixed height, you can count your climb. Twenty-five contour crossings on a ten-metre map is 250 metres of ascent, whether the ground is a staircase or a gentle ramp. Index contours — the slightly heavier lines — help you keep track; they usually fall every fifth line.

That lets you estimate time honestly. Allow roughly an extra minute for every ten metres of climbing on top of your flat walking pace, then add something for rough ground.

Contours also help you relocate. If you know you have crossed four contour lines since the last stream, and the map shows four between that stream and the col, you have a good idea where you stand. Add compass bearings and pacing, and you have a full toolkit.

Tarns, Pools and Putting It Into Practice

Wild swimmers should read contours closely too. Pools form where the gradient eases, so look for a tight cluster of contours that suddenly opens out — that flattening is where a stream drops its load and carves a pool. A small closed ring of contours on a shelf, especially with a stream running in and out, is often a tarn or a peaty hollow worth investigating.

Read the ground above your chosen pool as well. Tightly packed contours high in the catchment mean quick runoff, so a burn that looks inviting in the morning can be a different creature after afternoon rain. Plan swims for the walk down, not the walk up.

The best way to learn any of this is to test it. Before a walk, pick three points on the map and predict whether each will be steep or gentle. On the hill, stop at a viewpoint and match the slopes in front of you to the lines on the paper. Count your contour crossings on a climb and check the figure against the map. Within a few outings you will find yourself reading the hillside before you feel it underfoot — which is exactly when navigation becomes calm, and the day gets better.