Wildland Firefighting Practice Exam

How does the sun’s angle affect fire behavior?

1. It alters wind speed.

2. It changes moisture levels.

3. It affects slope exposure to heat.

4. It moderates temperature differences.

The correct answer is: It affects slope exposure to heat.

The sun's angle plays a significant role in influencing fire behavior, particularly through its effect on slope exposure to heat. When the sun is at a higher angle, it delivers more direct sunlight to certain areas, which can lead to increased heating of the slopes. This direct heating can dry out vegetation more rapidly, making it more susceptible to combustion. In contrast, areas that are shaded or receive less direct sunlight will retain moisture longer and have vegetation that is less likely to ignite. Additionally, steep slopes can enhance this effect; as the sun's angle increases, the south-facing slopes (in the Northern Hemisphere) receive more intense and prolonged sunlight compared to the north-facing slopes. This can create microclimates where fiery conditions are more favorable, leading to variations in fire behavior based on the terrain’s orientation to the sun. Understanding this relationship is crucial for firefighters as it directly influences how they strategize for containment and suppression of wildfires.