In which stage of fire development does smoke begin to become visible?

In the growth stage of fire development, smoke begins to become visible. This stage occurs after the initial ignition and small flames have developed. During the growth phase, the fire increases in intensity, and the combustion process produces considerable amounts of smoke and heat.

During this stage, the fire spreads as it consumes more fuel, leading to thicker and more visible smoke. The characteristics of the smoke can also change, indicating the materials that are burning. Recognizing the signs of this stage, such as visible smoke, is crucial for firefighters as it helps assess the fire’s intensity and potential danger, guiding tactical decisions about suppression efforts.

In contrast, the other stages—incipient, fully developed, and decay—do not focus on the visible production of smoke to the same extent as the growth stage, making it a key indicator of fire escalation.