Wildland Firefighting Practice Exam

Fires in a cooler environment during an inversion typically do what?

1. Become more volatile

2. Spread rapidly

3. Subside and become sluggish

4. Ignite uncontrollably

The correct answer is: Subside and become sluggish

Inversions often occur when a layer of warmer air traps cooler air near the surface. This layer can limit airflow and stabilize the atmosphere, which affects fire behavior. In a cooler environment during an inversion, fires tend to subside and become sluggish. This is because the cooler air can reduce the intensity of the fire by limiting the heat and moisture that usually rise and mix into the atmosphere, thereby hindering combustion and reducing fire spread. Additionally, the lack of wind associated with an inversion can prevent the fire from gaining momentum, resulting in a slower-burning and more subdued fire behavior. The other options imply a reaction to an environment that does not align with the nature of an inversion. For example, becoming more volatile or spread rapidly suggests conditions of instability and higher temperatures that are not typically associated with inversions. Similarly, the idea of igniting uncontrollably contradicts the characteristics of the stable air that usually suppresses fire behavior during an inversion period.