Before the Cloud Shuts You In

Poor visibility rarely arrives without warning. The cloud base drops, the drizzle sets in, and the ridge you were using as a handrail simply dissolves into grey. Hillwalkers who cope well in these conditions are not gifted with better eyesight; they have simply practised the basics until they are automatic. A little preparation before you leave the car park makes an enormous difference.

Fold your map to the section you need and keep it somewhere you can open with gloves on. Check the margin for magnetic variation — across Britain it currently sits within a degree or two of grid north, so at walking pace you can usually ignore it, but it pays to know. Then take a bearing while you can still see a landmark, and check it points where you expect. Confirm your start time too. In fog, time, distance and bearing become your only reliable evidence of position.

Taking a Bearing You Can Actually Follow

Lay the compass on the map with the long edge of the baseplate running between your position and your destination, and the direction-of-travel arrow pointing towards where you want to go. Rotate the bezel until the orienting lines inside it sit parallel with the eastings — the vertical grid lines — with the orienting arrow pointing to the top of the map. Read the number at the index line.

Now lift the compass off the map and hold it flat at chest height. Turn your whole body, not just the compass, until the red end of the magnetic needle sits neatly inside the orienting arrow, often called the shed. The direction-of-travel arrow now points along your bearing. Look up and pick out something small but definite in the mist — a boulder, a tussock, a patch of bare peat — walk to it, then repeat the process.

A few habits keep this accurate:

• Keep the map set to the ground underneath the compass so you can re-check quickly.
• Take bearings between features you can identify, not vague areas.
• If you have walked a leg and want to return, add or subtract 180 degrees for a back bearing.
• Never walk with the compass held in front of your face; use it to set direction, then walk a straight line.

Pacing: Turning Distance into Steps

Contours tell you how high you are; pacing tells you how far you have come. Measure your own stride on a known 100 metre stretch — a football pitch or a measured section of track. Most adults take between 60 and 65 double paces per 100 metres on flat ground, but the figure varies with leg length and terrain, so measure yours honestly.

Then count. Some walkers count every double pace; others count to ten and use a stone, a toggle, or a finger to mark each ten. The second method is far easier when you are tired, cold and concentrating on the ground underfoot. Adjust as the ground changes: add roughly a fifth more paces on gentle uphill, more again in deep heather, bog or loose scree, and fewer going downhill. Practise until you know your uphill and downhill figures too, not just your flat-ground one.

Reading the Ground Beneath the Fog

When you cannot see, the contours on the map are your eyes. Learn the shapes before you need them. Contour lines close together mean steep ground; widely spaced lines mean gentle slopes or flat moorland. Where a contour forms a sharp V, the point of the V tells you the direction of the stream or valley — the V points uphill for a re-entrant, and downhill for a spur. Counting contours between a known height and your target gives you a clear picture of how much climbing remains.

Combine that with your compass. If you are on a broad ridge and unsure which spur you have drifted onto, walk to the edge of the feature and take a bearing down the fall line. Compare it with the map and the ambiguity disappears. Spot heights, small lochans, and the distinctive shapes of crags all work as confirmation. The trick is to read them continuously rather than waiting until you are lost.

Aiming Off, Timing and Catching Features

A dead-straight bearing to a small target in fog is a gamble. Aim off deliberately: pick a point 100 or 200 metres to one side of your target, on a linear feature such as a stream or fence, then follow that feature to the goal. You will always know which way to turn when you hit it.

Timing works alongside pacing. Use a simple rule of roughly five kilometres per hour on the flat, plus about a minute for every ten metres of ascent, then add extra for bog, boulders, deep snow or tired legs. Check your watch at each leg and compare it with your pacing estimate; when the two disagree, stop and work out why.

Finally, always choose a catching feature — a lochan, a wall junction, a big obvious contour — beyond your target. If you reach it, you have gone too far, and you can turn back with confidence rather than guessing.

Making It Second Nature

None of this is difficult, but all of it is perishable. Take a bearing on a clear day and follow it for a kilometre. Pace out 100 metres in different terrain until the numbers stick. Practise folding your map in bad weather and taking a bearing with gloves on. The day the cloud comes down on a featureless plateau, you will be glad you did — and you will walk out of the mist exactly where you intended.