Wildland and Ground Cover Fires Practice Test

A temperature inversion acts like a lid for the lowest layer of the atmosphere. When a layer of warmer air sits above cooler air near the ground, vertical mixing is suppressed, so smoke from a ground fire can’t rise and disperse upward. Instead, it pools and stays low, often spreading with light winds. This keeps smoke near eye level, dramatically reducing visibility and increasing hazards for anyone operating on the ground. Inversions don’t have no effect, don’t push smoke upward, and don’t cause uniform dispersion or clearer conditions; they trap smoke low and concentrate it. This pattern is common on calm nights or in valleys and can persist until daytime heating breaks the inversion and convection resumes.