Level Up: Reading Terrain

Written by
Aaron YR

Level Up: Reading Terrain

Written by
Aaron YR

Level Up: Reading Terrain

Written by
Aaron YR
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In our previous entry into this series of Level Up, we discussed some of the folklore surrounding weather forecasting, and how it can be useful in predicting weather.

This installment addresses the nomenclature of the terrain we encounter when we are in the field. More importantly, we will discuss how to interpret what we're seeing when we do. An understanding of terrain will help you with everything from finding water to navigating.

Our emphasis here will be how to relate the terrain to both navigation and map reading, overland travel, and how to understand how terrain benefits or hinders your movement. Once the art and science of terrain reading is honed, you'll find your ability to dodge nature's wrath more complete.

At ISG, we typically divide skills and knowledge into two distinct categories; Urban and Rural. However, in this case it's not necessary. While the article will assess terrain from a rural perspective, the same features can be identified in urban environments. A firm grasp of how terrain influences runoff and vegetation can be critical in finding resources in an emergency, as well as ensuring you're not placing yourself in danger when you select a spot to hunker down. The purpose of the topographic map is to easily translate 3-dimensional features into 2 dimensional representations; these maps use contour lines which act as lines of equal height, so being able to read one can be an excellent tool when planning... both for urban or rural expeditions.

First, look at the following picture and as yourself "Where would I camp?"

Major Terrain Features

Copyright, ISG 2017

Hill (red circles) - The hill is an area of high ground in which the ground falls away in all directions. Hills are represented on topographic maps by contour lines arranged in concentric circles: the innermost of these is considered the hill top. Hills are prominently visible features both on the map and when viewed from the ground.

Depression (not depicted) - A depression is an area from within which you find higher ground in all directions. Depressions differ from typical contour lines in that they have hash marks that look like barbs coming off of them. From within a depression, you may find the ground saturated, or laden with dense vegetation or grass.

Saddle (blue line) - A saddle is an area of ground that features high ground on two sides, and lower ground on two sides. The saddle commonly connects hills and provides a good path between them.

Ridge (yellow line) -  Ridges feature high ground to one side, and lower ground to the other three.  The ridge differs from the saddle in that the relief in the three directions of lower elevation are variable. A ridge shows up on topographic maps as having a "tongue" or "U" shape, and while you're moving across a ridge, it may have a very gradual slope.

Valley (not depicted) - Valleys are, at their most basic, areas in which the land slopes upward in three directions, and downward in one. The valley differs from the draw in that it's generally a much larger feature. The Valley generally hosts year around water, which is fed by either a spring or mountainous region.

Minor Terrain Features

‍This image shows an intermountain valley, in which the lake would be a depression.

Draw (orange arrow) - A draw is an area through which water cuts through, carving a channel through higher terrain; due to this, when standing in a draw, the terrain will lead to higher ground in three of four directions. These draws often have residual water and dense vegetation. 

Spur (orange box) - A spur is a series of prominent points that falls away rapidly on three of four sides. The photo above illustrates spurs nicely, which can be seen in the upper leftmost corner.

Cliff (green circle) - A cliff is a sheer drop off from which the terrain contours quickly come within close proximity of one another, and in some cases, overlap. The name for this occurrence is 'carrying contours', and the value is considered to be the lowest present.

Terrain and Weather

There are a few important points to tie in to our discussion of terrain and weather that are largely forgotten:

  • Cold air sinks, so valley floors tend to be cooler than lower elevation ridges.
  • The windward side of mountains collects rain, so be cautious when camping on west facing slopes... especially in coastal climates.
  • The lee side of mountains tend to be arid: rain falls on the windward side of mountains and creates a "rain shadow" on the lee. Little or no rain falls in these areas.
  • Lee slops typically do have rivers and fresh water, however, often fed by mountain springs or snow/ice melt.
  • Hills provide lift for storm development; when the wind flows perpendicular to mountains or hills, there is potential for cloud or storm formation.
  • Lakes and standing water provide a source for both cloud development and animal/insect habitat.
  • Winds come from the mountains at night, and valleys during the day (Generally speaking).
  • Following water will ultimately lead you to mountains or the ocean.
  • Large rivers and beaches often have driftwood, which is very useful for shelter construction.

Terrain and Travel

Terrain affects transportation in every way. It doesn't matter if you're on foot, horse, off-road in a vehicle, or in an airplane, terrain features can change the way you travel. Our main concerns are on foot or off-roading, so let's briefly touch on how those are influenced. 

If you're moving on foot, your route is going to substantially impacted by terrain and your ability to read it, and this goes for off-road driving as well. The things you'll want to look for is grade (How far up and how fast), water crossings (and the draws they live in), open, low-laying areas that get saturated easily, and so forth. The goal is to stay out of trouble, so avoid the following terrain features for the following reasons:

  • Thick brush and undergrowth: Not only is this tough to pass through, if you're on foot it's a great way to pick up ticks, or stray sticks to the eye. Thorned vines can give cuts and tear clothing and equipment. In a vehicle, body damage can occur, and the ground is often deceptively soft/uneven.

  • Steep or boulder strewn hillsides and so forth are to be avoided. There are two predominant types of rocks we're looking for here: Talus and Scree. Both are loose rocks that result from weathering, and both are prone to shifting. Talus is large (if you need to hands to pick it up, it's Talus, but Talus can be boulder sized as well) and scree is typically smaller chunks. Both can cause dangerously unsteady conditions and are killer on vehicles and horses/pack animals. Flat ground is not a problem, but be especially careful when a grade is introduced.

  • Marsh and low lying areas with lush, short foliage (drainage areas). These areas tend to have significant populations of disease carrying insects, and bacteria flourishes in the warm stagnant waters. For foot travel, the big risks are insect exposure and wet feet, which can lead to immersion foot. For vehicles, you can quickly find yourself without a vehicle in marshes, and often there are no anchor points for recovery. The water depth can be very deceptive, and what looks like firm ground can instantly turn to muck a foot deep.

  • Rivers and Streams. It goes without saying that fording rivers can be very dangerous, whether or foot or in a vehicle. Rivers act as natural barriers, but are subject to nature's whim; watershed rainfall can cause quick fluctuations to depth and discharge, which need to be considered before you attempt to cross. Locating an ideal spot is more important than saving time. If your ride goes into the drink, you'll be a lot worse off. In general, look for depths of no more than a couple feet, slower moving water, and bedrock ledges that provide traction or footing.
If you're a child of the 80's, you remember this feeling. It's worse in real life, I'm sure.

These take time, energy (either calories or fuel), and risk to negotiate. They also tend to be away from natural lines of drift (obvious paths) that people will take instinctively. That can be of benefit, depending on the circumstances.

In a vehicle, being able to see terrain on the micro-scale can really make the difference between an easy off-road trek, or a damage causing nightmare. This is an art and science, and requires a high degree of familiarity with your vehicle's turn radius, height, wheel base, and departure/approach angles - all of which is discussed in our article on Overland Driving (in production). We will revisit these topics in later articles.

For now, just be aware that terrain will play a large part in overland travel whether your on foot, horseback, or in a vehicle.

Reading Terrain

Now that we have a baseline understanding for the terrain we encounter in the field, let's turn our attention to how we can use this to our advantage.

The first thing we consider when we're in the field is shelter; more than anything short of breathable oxygen, exposure to the elements have the most significant and immediate impact on our health. As such, we often need to be prepared to find shade, building material, fire starting material, wind breaks, or insulation. It helps to know where we can find materials that will help us. First of all, let's discuss the types of material.

Grasses, Saplings, and Vines

Grasses are useful as thatch, and sometimes able to be worked into nets or similar, grass is generally found in low lying areas and short in length. Longer grasses can be found, typically in fields (which low lying ridges). Saplings can likewise be used for making thatch, fish traps/drying racks, baskets and other items. Vines, such as Ivy, can be turned into improvised cordage.

In temperate climates, moss can often be found, especially on the north facing aspect of trees or rock faces. Don't think for a second you can use moss to determine direction, though. Moss grows everywhere, on everything, so you'll end up confidently lost trying to guess your direction by looking at moss. Moss can be used as an impromptu hemostatic, but is more wisely applied to improvised bedding. It can also be an indicator of direction.

Wood

‍Improvised cordage using Ivy.
  • Coniferous - Coniferous, or "evergreen" trees can be found in the foothills in which there is little soil and rocky detritus covers the ground. While in the rainforest, the predominant evergreens are Douglas Fir and Hemlock, lower lying areas near water can host Cedar (the bark of which burns nicely) and as you approach more arid climates, the Pines become more common. Pine are likewise common in the reaches of the Ozark uplift and southern Appalachia. Coniferous trees are characterized by flexibility, high amounts of pitch, and quick burning. They are considered a "soft" wood. Most importantly: Conifers have year around "boughs"(Hemlock, Fir, Pine) or "sprigs" (Cedar) that can be used as thatch for shelters and bedding.

This site had a ruined concrete foundation and plenty of trees; the concrete worked well as a fire reflector, while the trees and shelter broke the wind nicely.
  • Deciduous - In the fall and winter, Deciduous trees lose their foliage, which makes them less useful for improvising shelter. However, the fallen leaves can still be used as insulating bedding in a pinch.The deciduous trees common throughout the United States are often found lining the low lying areas around streams, rivers and lakes. These trees are hard woods, which burn very hot, and slowly, makes for stout building material. However, they lack the consistency of their coniferous cousins. Stands of deciduous trees very often indicate that a water sources in nearby, as these trees require ample amounts of water.

  • A Note on Wood: Do not try and burn sprigs, boughs or leaves. This is a common novice mistake, and they don't catch fire easily or burn long enough to be useful. They also tend to produce a lot of smoke (needles and sprigs in particular). Dried leaves can make a pretty passable insulation, if you've got a way to bag them up, however. Just watch for bugs.

Stone

‍‍An impromptu stone oven. The thin slate served well for cooking.

Stone is useful for a variety of tasks when establishing a camp or bivouac; it can be used as structural material for camps, fire rings, and primitive tools. Thin slabs of slate can be used as impromptu cook surfaces, and gravel is a useful component of the sand/charcoal water filter. Stone can usually be found in sites where there is terrain relief, such as hills. For the purpose of this article, we just need to be aware that stone is useful for a variety of things. Types of stone and their uses will be discussed later.

Sustenance

After establishing a camp, our next priority is finding a source of water and food, which is harder than it sounds. The importance analyzing the terrain for potential flooding, fire hazards, and seclusion from the elements becomes critical. Likewise, access to fuel for your fire and suitable water will either increase your workload and calories invested over calories returned, or decrease it.

Look at the photo at the top once more: Where's your camp? Whats your plan for food and water? Did you answer change?

We hope you enjoyed this installment of Level Up. Please feel free to share your pictures or experiences from your own primitive camps. Please join us as we continue the series with "Cloud Genera".

Cheers,

ISG Team