Which situation is indicated when you open a door and the smoke thins, but the smoke still fills the doorway?

When smoke thins upon opening a door but still fills the doorway, it indicates that the fire is likely below the door. This observation suggests that while the smoke has dispersed somewhat, it is still dense enough to be present at the entrance, which typically occurs when the source of the fire is lower than the level of the opening. In such scenarios, smoke from a fire that is burning below can rise and accumulate, potentially leading to clearer air just above the threshold or at higher elevations, as the smoke is being drawn upward by thermal dynamics.

This phenomenon indicates that the smoke movement is largely driven by the heat from the fire, resulting in a situation where the fire's intensity and location relative to the doorway can significantly affect visibility and air quality. Recognizing this is critical for ensuring safety and determining the best approach for confronting the fire. Understanding the relationship between smoke behavior and fire position is essential for effective firefighting tactics.