Wayfinding in Caves -

A Proposed Curriculum for a Short Course in Self Rescue

1996 NSS Convention, Salida Colorado
 

Presented by Dave Lemberg
Department of Geography
University of California at Santa Barbara


 



Philosophy / Goals

Many rescue calls stem from lost parties in caves.  To avoid the need for outside rescue for lost cavers, there are two sets of skills to be learned.  The first set of skills is wayfinding in caves (and enroute to and from the caves) - that is, how to avoid getting lost in the first place.  Developing good individual and group wayfinding skills and techniques will help avoid "lost in cave" incidents, and will also enhance the caving experience for the participants.  The second set of skills deals with reorientation - finding ones way back to the path after one loses one's way.  It stands to reason that if a party has managed to get to a section of the cave, they should generally be able to find their way back out.

Useful Tips

Look Back!
Pick out landmarks as you go, and label them.
Drop lots of trash behind you (only kidding).

Human Disorientation in a 3-Dimensional Enclosed Environment (Caves) Why We Get Lost

 For the Beginner or for the most advanced and experienced caver, the underground environment present special difficulties for wayfinding.  On the surface, most of our wayfinding is done in two dimensions.  In caves, we are faced with a three dimensional wayfinding task that can be very confusing.  Adding to this confusion is the complexity of the cave structure.  Caves are often described as being "maze-like", meaning that they have many branching passages, changes of direction (right, left, up, down, and various acute and oblique angles), changes in structure (breakdown, crawls, pits, etc.), and appearance (color, shape, consistency, etc.).  The perspective of the wayfinder changes as he or she looks in different directions.  The pathway going into the cave does not look like the pathway out of the cave (hence the need for the "look back" rule).  All of these properties are confusing - much more so than a standard garden labyrinth or maze puzzle on a sheet of paper.
It is also difficult to orient in cave systems.  The actual structure of the cave passages does not match our human intuition of the layout of these passages.  Much of our world is rectilinearly oriented, especially in a human-built environment.   Underground, this is not the case.  The passages are generally not rectilinear, and may curve in any direction.  The combination of twisting passages, darkness, and shadows results in a reduced perspective. The darkness itself is disorienting to some.  The horizon or field of view may be very close (restricted vistas).  We often can not see the entire passage at once - we can only see what is in the line of sight of our headlight beams.    In practice, the combination of various headlamps focusing in different directions and in different intensities presents a very confusing tableau.  This distorts our ability to estimate distances.  The restricted line of sight in caves limits our ability to grasp the extent of our surroundings.  With a limited visual horizon, distance may be estimated a function of the time and/or effort expended in getting from one location to another.  Another disorienting aspect of caving is the task of moving through the three-dimensional space of the cave system.  Most human wayfinding problems involve paths in 360 degrees of two-dimensional space.  Moving through a cave, one must simultaneously orient both vertically and horizontally.  The way out is generally up (or occasionally down) rather than just backward.

The cues for orientation underground are also different than those on the surface.  There are no sky cues - no sun, no moon, and no stars.  Shadows are not a directional cue as they are on the surface.  The lack of general surface cues such as horizons and the sun may  also create distortions in the perception of time and distance underground.  Without a sky (and without a watch), there is no external reference to the passage of time.  Time may be measured in terms of the rhythms of caving.  Such rhythms include carbide or battery changes and the cycle of brightness of headlamps.  Low light levels at the end of the carbide charge or battery life may also distort distance sense.  In low light levels, the visual perception of the cave passage deteriorates.  Features become fuzzy, shadows become less distinct, colors fade into gray scales, and textures become blurry.

Time may also be measured in terms of bodily functions - hunger, thirst, cold, stress, and fatigue.  In extreme conditions, these bodily stress may distort time perception in themselves.  According to some cavers, the greater the level of fatigue, the greater the perceived time and distance for any interval of effort.  Time measurement may also be a function of actions or travel.  Time and distance are to some extent interchangeable so that one may say that a destination is 2500 feet into the cave, or they may say that the same destination is one hour into the cave.  What is one hour in to one group of cavers may be a half hour to an experienced group in good condition, and two hours to a group of cave photographers.  Time perception for a group of cavers may well be a function of the slowest caver in the group.  Indeed, a slow caver may very well disrupt the spatiotemporal orientation of an experienced caver who would normally traverse the route much faster.

Caving may also disrupt our circadian rhythms of time.  Long cave trips may involve over well over 24 hours of continuous activity.  Even shorter cave trips may infringe on normal sleeping periods.  Combinations of long drives and long cave trips may create symptoms of disorientation and discomfort similar to "jet lag".  Symptoms of jet lag include fatigue, disorientation, lack of energy and motivation, dehydration, and "losing it" (irritation and unreasonable behavior).  Cavers should take into account that a long drive followed by a long cave trip can cause time disruption equivilent to flying halfway around the world.

Other difficulties stem from the way a party goes through a cave.  There are different speeds and styles of caving.  Often a trip leader wants to get to a specific destination quickly for surveying, sightseeing, photography, etc.  The type of trip may determine how much the caver learns about the cave.  Surveyors and photographers may come out of the cave with detailed observations that synthesize into a comprehensive knowledge of the route.  A fast "tourist trip" or an "in-and-out" scientific collection trip does not generally allow the caver the leisure to build wayfinding knowledge.  The party moves quickly through at the leader's pace, too quickly for the other members to do the sort of observation required to build route knowledge.  At this pace, the other members of the group may become passive followers, unable to find their way without assistance.  Depending on the person's position in line, there may be perspective problems.  It is difficult to concentrate on learning the details of the cave passage if your perspective is dominated or blocked by boots, back, helmet, or rear-end of the person in front of you.

There are also special problems involved in finding cave entrances and finding one's way back to the vehicle or base camp.  One major problem is finding the cave entrance.  The entrance may be hidden by vegetation, by rugged terrain, or by other similar looking holes, pits, etc.   There are few distinguishing features in may karst landscapes.  Often the printed or oral directions are hard to follow (maps seem to be easier to follow than oral directions), inaccurate, or distorted.  Distances may be wrong.  The "big tree on the hillside" may look no different than all of the other big trees on the mountain, or on the adjacent mountains for that matter.  There may be seasonal changes in the landscape - a clear view through the trees in the winter may disappear with the summer foliage.  Weather conditions such as rain or fog may obscure views.  Darkness is a problem, especially on return trips from caves.

When one leaves a cave, there may be many problems with finding one's way back.  Navigating on the surface in darkness creates many of the same problems as in cave navigation.  The features and landmarks look different in the opposite direction.  Perspective may alter with altitude - one may look up the trail at a mountainside through the trees from the "flats", but looking down from the cave, one will see a sea of foliage and no trail.  The problem may be compounded by the fact that many cave trips begin in daylight and end in darkness.  The same difficulties one finds in underground wayfinding are actually worse on the surface in that the cues and landmarks one may have recorded earlier in the daylight are no longer visible in the limited beam of the headlight.  Distant landmarks used for wayfinding  in the daylight may not be visible at all after dark.  Add to the problem that one is likely to be fatigued and dehydrated after a long day of caving, and one has the recipe for fatigue and disorientation.

Skills to be Learned

Observation Skills - Learning a Cave

The best method to avoid losing your way in a cave is to learn the cave as you go.  Learning the cave involves constantly observing the rooms and passages with all of you senses and recording your images and impressions in some systematic fashion.   We can start with a memory exercise.  Think back to your last caving experience.  Close your eyes and let the memories flow.  Visualize the passage.  What do you see?  What are the textures of the walls?  What are the colors?  Is the passage wet or dry, muddy or dusty?  Is it pretty or dull?  What is the most distinguishing feature of that section of passage?  From how far away can this feature be seen?  How big is the passage?   Is it sloping up or down?  How do the shadows shift as you move forward?  You get a lot of information from your eyes, even in an environment where visually oriented creatures are at a disadvantage.

Now think of your other sensory systems.  What did the passage sound like?  Do you remember dripping sounds, water flowing, wind sounds, etc.?  Did your voices echo?  What did your feet sound like on the floor? Ringing on rock? Crunching through gravel?  Slurping through mud?

What did the passage smell like?  Clean rock and water, mud, decaying detritus, or guano and amberat; they all have their distinctive smells.  Or was the smell of the cave overwhelmed by the sweet smell of carbide and ripe coveralls?

What did the passage feel like?  Rough, smooth, wet, dry, greasy, dusty, gravelly, muddy, bouldery, etc.  Where are you feeling the passage - with your feet, your knees, your hands, your whole body, the top of your helmet with a "clunk"?    How warm or cold was the passage?  Was there a draft blowing through?

We have gone through the obvious four senses: sight hearing, smell, and touch.  We have many others.  Think of balance.  Was the passage flat or sloping?   In which direction?  Were you constantly changing your balance like walking over breakdown.  Think of your entire body.  Was it easy going or were you exerting yourself?  How were you moving - walking, crawling, squeezing, climbing, chimneying, ascending, rappeling, etc.?

So far we have just been remembering sensory impressions.  The next step is to integrate these impressions with prior knowledge to attach meaning to them.  Think about the passage again.  Try to classify the passage.  Use whatever type of classification that means something to you.  Go around the group and state them aloud.

You probably heard anything from shape and size, to geological jargon, to aesthetic commentary.  Everyone has their own manner of classifying their surroundings and all are legitimate.  Some, though are more effective in generating route knowledge or map knowledge of a cave than others.  A caver has route knowledge of a cave when he or she can describe or follow a path from one location to another.  The caver knows a route from the entrance to "the Big Room", but could not stand at the entrance and point the direction to "the Big Room"  or how far away it was in a straight line.  To achieve map knowledge of the cave, the caver would know the routes and the cave structure well enough to be able to estimate where to look for a 30' long connecting passage to complete a loop from the "Big Room" to "the Main Passage" if the "Main Passage" passes within 30' of the "Big Room".  While such a task is easy on a map, it is exceedingly difficult in a cave in one's head, in three-dimensions.

Most cavers never attain map knowledge of a cave.  Fortunately, route knowledge is all that is necessary to avoid major disorientation in cave.