What are the warning signs of a backdraft?

A backdraft is a dangerous phenomenon that occurs in a fire when oxygen is suddenly reintroduced into a space that is filled with hot gases and smoke. The correct choice highlights two key warning signs: a sudden inrush of air and heavy smoke from hot gases.

When a door or window is opened in a confined space with smoldering combustibles, the influx of oxygen can trigger a rapid combustion reaction. This often manifests as a strong rush of flames and fire, which can be seen visually and sensed through the movement of air. The presence of heavy smoke indicates that incomplete combustion has occurred, and the situation is ripe for a backdraft.

Recognizing these signs is essential for safety, as they provide crucial information to firefighters about the potential for explosive fire behavior in an enclosed environment. Understanding the dynamics of a fire, including the role of oxygen and the state of the gases present, is critical for fire control and prevention strategies.