Which characteristic describes poor combustion in fire stages?

Poor combustion in fire stages is characterized by dense smoke and poor visibility. This occurs because inadequate combustion leads to an incomplete burn of the fuel, which produces a higher volume of smoke that is rich in particulates and unburned hydrocarbons. When a fire is burning inefficiently, the smoke generated is thick and dark, often resulting in reduced visibility in the area around the fire. This is a critical safety concern, as it can impede evacuation procedures and make it difficult for firefighting efforts to locate and address the fire effectively.

In contrast, good combustion typically results in cleaner, lighter smoke and can actually produce more heat and light, which translates to better visibility. Other characteristics of poor combustion, such as cool temperatures, typically indicate that the fire is not burning efficiently or is smoldering rather than consuming fuel effectively. High radiative feedback, meanwhile, refers to the heat being radiated away from the fire rather than indicating the quality of combustion itself. Thus, the presence of dense smoke and poor visibility is a definitive characteristic of poor combustion conditions.