How can you navigate / determine your location in thick fog?

Question

Are there any good hints, tips and ways you can use to navigate around and find your location in thick fog (apart from a GPS)?

Answer 1

With fog, the only thing you're losing is extended visibility. This shouldn't throw off your plan too much, unless you were navigating by watching far away landmarks.

If you were on a trail, stay on it. There's no need to wander around. If you can't see anything and traveling is becoming dangerous or you're not sure where you're going, then stop and wait for the fog to lift.

If it's getting dark, you might have to setup camp. Hope you have an emergency kit!

Ultimately it's a judgement call. If you think you can keep marching on without getting lost, then don't worry about the fog. But if the fog is too thick, stop and wait it out. Remember, patience is a virtue :)

Answer 2

There's a whole bunch of standard map and compass techniques you can use without a GPS.

If you know your location before the fog came down, then you're not lost - you just can't see so far. Change your navigation strategy to have shorter legs, and pick tick points that will be within your vision. Pay particular attention to changes in trail direction and contour interpretation. If you have a good handrail feature (path/river/fence) use that too.

If you are 'lost' and need to re-locate yourself, start by looking around you. Are you by a path or stream, and if so, what direction is it going. What's the terrain doing around you. In particular, in the mountains, what is the slope aspect? (i.e. what's the compass bearing of the 'fall line'). If you have a (correctly set!) altimeter watch that can help reduce the possibilities too.

If you're lucky this will be enough to give you a definitive fix (or enough clues to tell you which way to go, even if you're not 100% sure of position.

But often, there aren't enough definitive clues within sight to fix your position. If so, it's time to move! Not far - maybe 100m or so. Choose the direction to move in based on your previous guesses (ie, pick directions where the presence/absence of particular expected features en route will narrow the possibilities) and obviously avoid directions that could take you near steep drops. Add the clues from your new position to those of the old one. Repeat, if necessary.

There's a whole bunch of books on navigation. My favourite is this one.

http://www.amazon.co.uk/Ultimate-Navigation-Manual-Lyle-Brotherton/dp/0007424604

Answer 3

If you know about the wind then that might help you. For example, a northerly wind blows from the north to the south, likewise an easterly wind is a wind that originates in the east and blows west and so on.

Answer 4

Pacing and timing can be used to aid navigation in poor visibility. Both methods improve as you gain experience by practicing pacing and timing over different terrains.

• Pacing by counting steps (beads on your compass lanyard or a mechanical counter will help you avoid loosing count) to estimate distance travelled from a known location.
• Timing based on, for example, Naismith's Rule to estimate distance from a known location.

You could also use a rope of known length to measure distance.

A great example is safely navigating off the summit of Ben Nevis which requires following a bearing of 231 degrees for 150 metres, then following a bearing of 282 degrees.

Answer 5

according to the boyscout handbook you can use moss (apparently it usualy/always grows on the North side of the tree...)

It is generally believed that in northern latitudes, the north side of trees and rocks will generally have more luxuriant moss growth on average than other sides. This is assumed to be because the sun on the south side creates a dry environment. South of the equator the reverse would be true. However, naturalists feel that mosses grow on the damper side of trees and rocks.[3] In some cases, such as sunny climates in temperate northern latitudes, this will be the shaded north side of the tree or rock. On steep slopes it may be the uphill side. For mosses that grow on tree branches, this is generally the upper side of the branch on horizontally growing sections or near the crotch. In cool damp cloudy climates, all sides of tree trunks and rocks may be equally damp enough for mosses. And different species of mosses have different moisture and sun requirements so will grow on different sections of the same tree or rock.

Wikipedia page on Moss

Answer 6

If you need to walk on a compass bearing in poor visibility, stand still, and send someone out in front of you on the correct bearing for a distance (probably as far as you can see). Have them stand still, then walk to them. Repeat. It's slow going, but you will be walking on the correct bearing, and more accurate than just holding the compass out in front of you.

Location finding is a bit trickier - I guess not being lost in the first place is the best idea! Look for any features that may be visible that would be on the map, or any identifiable features that you come across while walking. If you think you know roughly where you are, walk to a feature, like a stream, and if you don't find it then you need to reassess.

Answer 7

This depends of course on the tools you have and what your overall situation is.

For example, if you know that you are on a certain path and you have a compass, and if you are on a slope, you can try to figure out the direction of the slope and compare that to the slopes along the path you are on using your topographic map.