Drone Pilot Practice Exam

Which of the following conditions could lead to the visibility of thermal plumes?

1. High humidity levels

2. Strong wind patterns

3. Large amounts of vertically directed gases

4. Stable temperatures

The correct answer is: Large amounts of vertically directed gases

Thermal plumes are visible columns of warm air that rise through cooler air due to differences in temperature and density. The presence of large amounts of vertically directed gases is critical in creating these thermal plumes. When significant heat is emitted from a source, such as an industrial facility or a fire, it can cause the surrounding air to heat up rapidly. If there are substantial quantities of gas being expelled, the warmer, less dense air will rise, creating a visible thermal plume. This phenomenon is particularly prominent in environments where there is enough thermal energy to create a dramatic difference in the temperature between the gases and the surrounding air, promoting rapid ascent. In contrast, high humidity levels can result in the formation of clouds or mist that may obscure the visibility of thermal plumes rather than enhance it. Strong wind patterns can disperse the rising warm air, preventing the establishment of distinct plumes. While stable temperatures might not directly inhibit the formation of thermal plumes, they typically do not contribute to the strong thermal differences necessary for clear visibility of the plumes. Thus, large amounts of vertically directed gases serve as the primary factor in generating visible thermal plumes.