Quick Answer
Understanding slope angles can greatly enhance your survival strategy by allowing you to identify potential risks, find safe routes, and locate water sources. This knowledge enables you to make more informed decisions in the wilderness. Knowing the slope angle of your surroundings can be a lifesaver in emergency situations.
Understanding Contours
When reading a topographic map, contours represent the shape and elevation of the terrain. Contours are lines that connect points of equal elevation, forming a series of concentric arcs around hills, valleys, and ridges. The closer the contours, the steeper the slope. For example, a contour interval of 20 feet (6 meters) means that a change in elevation of 20 feet is represented by a change in contour line. This interval can vary depending on the map scale.
Identifying Slope Angles
To estimate the slope angle, look at the contour interval and the distance between the contour lines. A good rule of thumb is to use the following rough estimates:
- 1:1 slope (45°): Contour lines are close together, often less than 10 feet (3 meters) apart.
- 2:1 slope (33.7°): Contour lines are about 10-20 feet (3-6 meters) apart.
- 3:1 slope (20°): Contour lines are about 20-30 feet (6-9 meters) apart.
Keep in mind that these are rough estimates and can vary depending on the terrain and map scale.
Locating Water Sources
Slope angles can also indicate the presence of water sources. Look for areas with a gentle slope (less than 10°) and a high concentration of contour lines. These areas tend to be more likely to have a water source, such as a stream or a spring. In a survival situation, being able to locate a water source can be a lifesaver.
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