Staying found - The tricks

The basic art in map reading is being able to relate the map to the ground. Practised map readers can look at a map and almost summon up a photographic image of what the ground ahead and around will be. Reaching this level of skill takes a bit of time, but it is easy to practice and an essential skill to develop. With good map reading skills, the three key uses are then:

1. Pinpointing location: the ability to look at a map and say "that hill is over there", "the ground here is falling away steeply to the right", "that small stream is just behind me" so I must be here right now.
2. Anticipating: with a good image of the map in your mind (study it in the hut the night before), you should always be anticipating what comes next: "over this rise, the ground should drop away quickly and I should see a small rocky knoll ahead to my right", "I've got another 200m to go then the ridge should swing sharply to the right and begin to descend". This kind of anticipation acts as an early warning of errors in navigation. Immediately, the ground will start to look and feel different from what you were expecting which is a sure sign that it is time to stop and check your location before making a more serious error.
3. Route planning: perhaps the most important use of good map reading skills is being able to plan a safe route through off-piste terrain. Throughout this guide, we have stressed the importance of effective route planning to avoid potential avalanche slopes, stay clear of crevasse zones and steer around steep ground. Careful reading of the map to recognise and avoid this dangerous terrain is one of your main weapons in staying safe!

2. Using the compass

The purpose of a compass is to help you relate where you on the map to where you are on the ground. Good navigation compasses will have a number of features to help you do this.

There are four basic techniques:

• Setting the map: relating the map to the ground is much easier if the map is oriented the same way as the ground. If you are facing North, the map should be upright. If you are facing South, the map should be upside down. To set the map, turn the degree dial to North (0o). Place the compass on the map with the orientation lines pointing the same way as the North gridlines. Rotate the map until the needle too points North. The map is now “set” or aligned accurately with the ground , and it should be easier to relate the map features to the ground features to locate yourself.
• Taking a bearing from the map: the most common and important use of the compass is to take bearings from the map to set a course along the ground. This is simple to do. Lay the compass on the map with the side running from where you are (or where you think you are!) to where you want to go. Turn the degree dial until the orienting lines align with the North facing gridlines (making sure you don’t get this upside down!). Read off the direction in which the orienting arrows now point. This is the grid bearing. Remove the compass from the map and add the magnetic correction . Rotate the compass so that the needle is aligned with the orientation lines. The direction of travel arrow will now point in the direction you want to go. In good visibility, you should be able to see the next point, and the bearing simply helps to confirm the point for which you need to aim. In poor visibility, or in whiteout conditions (covered later) you may need to follow the bearing without the aid of a visual reference. Getting this basic skill right is pretty important!

• Taking a bearing from the ground: taking a ground bearing is less often used, but it can be helpful in working out where you are by sighting off a known point. The process is very simple. Point the direction of travel arrow at the object whose location you know – typically the top of some nearby peak. Turn the degree dial until the needle lines up with the orientation arrows. Subtract your magnetic correction . Place the compass on the map with the side against your known point and then rotate the compass until the orientation lines point in the same direction as the North-South gridlines. Your position is somewhere along the side the compass which hopefully should be enough information to work out where you are on the map, especially if you know the altitude.
• Slope aspect: fixing a location by slope aspect is an incredibly useful skill off-piste since it is often (especially in conditions of poor visibility) the only information you have. The process works like this (see diagram below). Suppose you are descending South on skis and are not quite sure whether you are at Point A or Point B. Visibility is down to 10m, and there are no obvious landmarks in sight. Continuing South from A will be perfectly safe, but if you are at B it will take you straight into the crevasse field. The trick is to measure the aspect of the slope you are on since at A it will be due South. At B it will be almost West. To do this, take a ground bearing sighting down the fall line of the slope. Comparing the slope aspect with what you expect from the map will help you immediately to tell whether you are at A or B. Clearly this techniques relies on you having some idea of where you are in the first place, but it can be key in making precise corrections to your position in conditions of poor visibility.

3. Using the altimeter

Good navigation is all about using the information available to make a judgement about location and route finding. The altimeter provides a vital piece of additional information – your vertical height. Off-piste this information can be incredibly valuable in situations such as:

• Following a ridge: where you may need to take a turn at a particular point to make a safe descent between cliffs or steep ground. Vertical height may be the only way of judging how far along the ridge you have travelled.
• On a ski descent: given the difficulties of measuring distance when descending on skis, knowing your vertical height may be the only way to get an accurate fix on your position.
• Holding a line on a traverse: when traversing, there is an almost inevitable tendency to drift downhill which can drag you off course. A similar effect happens when moving forward into a strong wind; your route almost inevitably tends to veer away from the wind as you seek some protection! Having a continuous read on your height can help to prevent this tendency.

The altimeter becomes even more important in white-out conditions when vertical height and (perhaps) slope aspect may be the only pieces of information you have.
The altimeter is a great tool, but there are a couple of simple tips worth bearing in mind:

• An altimeter works by sensing changes in pressure, so the reading will change if there is a general change in atmospheric pressure. These changes can send your reading out by as much as 50-100m even in quite a short space of time. This means it is vitally important to “zero” the altimeter by re-setting it to the current height every time you reach a known point (such as the summit of a peak, crossing a col, or even just passing an obvious landmark). Equally, be aware that the reading you get at any time may not be completely accurate, particularly if it is a couple of hours since you zeroed the altimeter or if the weather has changed significantly.
• Another useful tip is that the altimeter can be used as a simple barometer during your overnight stop by measuring the difference in height reading between going to bed and waking up the next morning. Your actual height will not have changed overnight so if the altimeter reading has fallen, it means the atmospheric pressure must have risen. If the height reading has increased, it means the pressure must have fallen. Most of the electronic altimeters also have a barometric function which will plot a graph of pressure changes during the night.

4. Using a GPS

GPS is a global navigation system by which a GPS receiver communicates with orbiting US military satellites that send position information from which the GPS “triangulates” its own position on earth. There are 24 satellites in orbit and the GPS must “lock on” to at least 3 of these to establish its 2-dimensional position (lat and long) and at least 4 satellites to also calculate its altitude (location in 3-dimensions). GPS will not work under “cover” – inside buildings or underground – and the receiver must have an uninterrupted view of the sky for greatest accuracy. Use of this system is free and the outlay for a GPS receiver is modest. The system is very accurate and has revolutionised land and sea navigation.

The basic features and functions are:

• Map Datum and Position Format: these are references related to the geographic area you are in and the map series you are working from. The GPS must be set to the correct datum and format otherwise you can’t relate to the map accurately. For example, the Chamonix map is labelled GPS Compatible and it tells you that the datum/format is UTM-WGS84. Tip: you can always calculate the co-ordinates of your present location using a local map and compare them to the waypoint coordinates of your GPS to ensure you have set the datum/format correctly.
• Waypoint: a point or location, either of your present location or a point you want to go to. You might, for example:
  · Create a waypoint: where you have been, perhaps at a food cache, a tented camp or a snow hole you want to find again. A waypoint is created easily, usually by the press of a button. Memory for waypoints is always limited (usually 500 to 1000) but this is hardly a concern when you’re travelling on skis day by day with time in the evenings to programme your GPS.
  · Input a waypoint: to help you navigate to a hut on a featureless glacier in a whiteout or to find your way to a col. To do this you need to programme in the grid reference from your map (as eastings and northings – reading the numbers across the top of the map first, left to right – then the numbers on the side, from bottom to top.) The number of figures required for the co-ordinates varies with the map datum used.
• A Route: is a series of waypoints that are connected or grouped (in the memory), as in joining the dots. A route is useful if you need to travel from A to B then to C but you don’t have or want to follow a track or pre-set route. You might want to create a route of a limited number of waypoints for each day of touring, with each waypoint marking a significant feature enroute. A GPS will have a limited memory for creating routes and for the number of waypoints allowed per route.
• A Track: is a continuous log of a journey, as in a “breadcrumb trail”. Data is gathered continuously and automatically when the TRACK LOG is set to ON
  · Some units allow you to change how frequently data is recorded, which is arguably useful if you wanted to create a more detailed track (through a heavily crevassed glacier).
  · A track memory is limited and when it is full it will “wrap” – that is, it will record over the data collected at the beginning of the track log. You need to watch this and when the memory is close to 100% you can name and save the track for later reference. For a long track you may therefore have to record it and name it in sequential segments e.g. Haute Route 1, Haute Route 2 etc. A GPS will have a limited memory for creating tracks. Most units will have a trackback feature, which allows you to retrace your steps, useful for finding your way back to the refuge if the weather turns nasty!
  Be aware, however, of the following limitations of tracks:
  · The unit must have a continuous sky view or it will record anomalies in the track. For example, if reception is broken, the unit will join the last known point with the point where reception is resumed with a straight line, when if fact you may have circled around an object (e.g. a cliff) during the time that reception failed.
  · The unit must be turned on to record a track and therefore is using battery power.
  · When you stop moving, the GPS still records breadcrumbs, which may be anomalous to your actual location, due to normal variations in receiver reception and therefore will misdirect anyone attempting to follow the track subsequently which is why you should always stay found on your map as well as using a GPS. If you can’t read a map and your GPS fails, you run out of batteries or you lose it, you’re in trouble.
• Battery life: this is estimated for the model, but often overrated and affected by how much programming you do. You can easily use a set of batteries per day if the unit is on continuously.
• Accuracy: Garmin claims that its units are accurate on average to 7 to 15 metres, although the display will often claim to be reading more accurately than this.

5. Navigating in a white out

White-outs in snow bring conditions of almost zero visibility. Until you have been in one, it is difficult to imagine just how disorientating this can be. Distances, slope angles, directions, and speeds become impossible to judge. There are no features to give the eye something to ground on and it can be a dizzying, bewildering experience. You can be 5 feet away from a sheer drop and have no idea about it until you blunder over the edge. If the white-out is accompanied by strong wind or blizzard conditions it can be easy to begin to lose control of the situation. This is the time for calm and careful route planning. The respite provided by a group shelter can be a God-send!

The sequence for safe navigation out in a white-out is as follows:

1. Plan a route: the worst thing you can do is to struggle on blindly in the hope that you might reach your destination. In difficult conditions you may need to modify your route or even abandon your original objective. Sit down, study the map, choose a safe and sensible route, communicate the route to the whole group and appoint one person as your principal navigator. If the conditions are really bad, you may even consider digging a shelter and staying put until conditions improve.
2. Set a bearing: with no visibility, you will have to rely on following a compass bearing. Once your route is clear, use the techniques described to set a bearing to follow for the first leg of your route. Get someone to double check the bearing since this is no time to be making mistakes.
3. Follow the bearing: in poor visibility with no landmarks to fix your direction on, it can be easy to drift away from your planned bearing. This is particularly the case in strong wind or following a sloping traverse where there is always the tendency to drift downhill. The trick to avoid this is to send one person out in front about 10-15m ahead of the group (less if the visibility is lower!). The navigator comes second and carries the compass in their hand at all times. As soon as the lead person begins to drift to the left or the right, the navigator can shout instructions to bring them back on course. Multiple small corrections like this should help to maintain an accurate bearing even in conditions of zero visibility.
4. Use the altimeter (and GPS if you have it): remember the altimeter keeps working even in white-out conditions. Refer to it often and use anticipation to make sure you are always where you think you are. Errors are much easier to correct if they are caught early. This is also a great time to get the GPS out if you have it with you, especially so you can periodically plot your current position on your map.
5. Use slope aspect: slope aspect is the other piece of local information you can rely on to keep checking your location. In very bad visibility (where slope angle is difficult to read), a good trick is to throw snowballs down (what you think is) the slope. Even in very poor visibility, this should help you to identify the fall line which is all you need to get a feel the direction of the slope.
6. Look out for small features: in poor visibility, even tiny variations in the slope angle, or rocky outcrops become much easier to see. Study the map carefully and keep a close eye out for any pointers that can help you to keep confirming your location.
7. Consider roping up: if there is any steep group or crevasses nearby, this could be a very good time to rope up. You’ll be moving slowly in any case so there won’t be much time loss. Follow the process described in the section on crevasses.

6. Other tricks

Navigation is an art as much as a science. Really good navigators always have a good sense of where they are and what to expect next. That way, each new piece of information can be fed in and checked against their expectations – either to confirm the location or to get an early warning of any drifting off course.

Good navigators do also make use of a number of additional tricks:

• Following tracks: much of the time, we end up following routes which others have already taken and in snow everyone leaves tracks. Following tracks tends to give a lot of reassurance and has the advantages of (1) being easy to do, and (2) being a less effort that having to break new tracks in fresh or deep snow. On a popular off-piste route such as the Valle Blanche there will almost always be tracks to follow, and is a perfectly acceptable means of navigation provided you remember to watch out for the following traps:
  • A set of tracks does not mean a route is safe. Snow conditions are constantly changing and just because 20 people have safely crossed a snow-bridge or an avalanche prone slope does not mean the bridge won’t collapse or the slope won’t give way when you cross it. Use all your knowledge and skills to make an independent assessment of the safety of any route rather than just assuming it will be ok because some-one has been there before.
  • Tracks may not be going where you want to go – there are few things worse than merrily following tracks only to discover they lead you on a completely different route to the one you intended!
  • Finally, don’t forget that the person who made the tracks may be just as lost as you are!
• Using guidebooks: many popular routes have guide books with route descriptions. These can be either very helpful or potentially misleading. Advantages: a good guide book description can be a great help in navigating potentially tricky areas or in finding tricky routes out in difficult terrain. Disadvantages: some guide books contain mistakes, and even if the guide is accurate it’s of no use once you’ve strayed off the intended route. By all means use a guide book as an aid, but never rely on it as your sole means of navigation or treat it as a substitute for a good map.
• Aiming off: is a great technique for giving extra certainty to your navigation. Suppose that you are navigating on a compass bearing aiming to hit a junction over a steeply banked stream (see diagram above). The risk is that you might miss your target by a small amount and not be sure whether it lies to your left or to your right. By “aiming off” you follow a bearing (or line of sight) slightly to one side of your destination. In the example below, you might aim off 3-4o to be sure of hitting the stream to the left of the junction. When you hit the stream bank, you know for sure (barring major navigational disasters!) that your destination lies to the right. Aiming off can be a great time saver in poor visibility and helps to avoid pointless blundering about.

• Practice, practice, practice: navigation needs practice. Plenty of practice in calm safe environments will make your life that much less stressful when you suddenly have to call on your skills in difficult conditions. One of the most important aspects of good navigation is the mindset of always knowing where you are and again, this only comes with practice! Always take the opportunity to practice your navigation skills even in places where you feel they’re not really needed. A day spent walking in the hills or even just skiing around on the piste can be good safe opportunities. Orienteering events are a great way of practicing your navigation skills. For those who are feeling fit enough mountain marathons are excellent too!