Navigating in whiteout, when the ground and sky are the same colour

Treat the sections below as a sequence. With whiteout navigation, getting the early decisions right makes the later ones much easier.

Why it is different

In whiteout, uniform cloud and snow remove the horizon, shadows and any sense of scale. Slope angle becomes very difficult to judge, and people report walking into slopes they did not see.

Every visual technique for navigation stops working simultaneously. With no visual reference the inner ear takes over and gets it wrong, which is why people in whiteout report level ground that turns out to be a slope, and why a party can drift steadily downhill convinced it is contouring.

The three tools that remain

A bearing gives direction, pacing gives distance, and timing gives a cross-check on both. These have to be practised in good conditions, because a whiteout is not where to learn pacing.

A party that knows its pace count per hundred metres on flat and on climb can navigate accurately without seeing anything. Splitting the roles helps as much as the technique, since one person holding the bearing and doing nothing else, while somebody else counts paces and a third watches the clock, catches errors that one person doing all three will not.

Leapfrogging

Sending one person ahead on the bearing until they are at the limit of visibility gives a visible reference point. They stop, are aligned by the person behind, and the party moves up.

It is slow, effective and the standard technique for accurate travel in no visibility. It also measures distance, because each leg is roughly the limit of visibility and counting the legs gives an independent check on the pacing, which is worth having when the pacing is the thing you are relying on.

The hazards you cannot see

Cornices overhang the leeward edge of ridges and break well back from the apparent edge. Convex slopes hide what is below them, and in flat light there is no visual cue at all.

Locally, navigating well away from ridge edges, on a deliberate offset, is the standard precaution. A cornice cannot be seen from above at all, since the break line lies back underneath the snow you are standing on, which is why the taught margin is to stay well clear of any ridge crest rather than to judge an edge you think you can identify.

Aiming off and catching features

Deliberately aiming to one side of a target means you know which way to turn when you reach a linear feature. Choosing a catching feature beyond the target — a stream, a wall, a slope change — tells you when you have gone too far. Both techniques matter far more when you cannot see, which is exactly when people forget them.

The detail that matters: the companion to them is the attack point: navigate first to a large feature you cannot miss and only then take a short precise leg from it, because a two-hundred-metre bearing carries a fraction of the error of a two-kilometre one.

How much of that applies depends on the terrain you are actually in.

A compass is only as good as what is sitting next to it

The needle is deflected by anything magnetic within a few centimetres, and phones, cameras, avalanche transceivers, radios and the magnetic closures now built into some pockets and glove cuffs will all move a bearing by enough to matter. The error scales with distance: three or four degrees is invisible over a hundred metres and puts a party well off line over two kilometres, which is precisely the distance you might hold a single bearing in no visibility. The habit is to take the bearing with the compass held well clear of the body, then check it again with everything stowed differently, and to distrust a needle that disagrees with the slope you can feel under your feet.

A few known areas of magnetic rock produce the same deflection across whole hillsides, which is recorded on the maps and in guidebooks for those specific places and is worth looking up before relying on a bearing there.

The takeaway

Bearing, pacing, timing, and aim off. Everything visual has gone.

The route rewards patience more than equipment.