How is the explosive growth stage defined in a fire's progression?

The explosive growth stage of a fire's progression is characterized by a rapid increase in fire development. During this phase, a fire transitions from its initial stages to a more aggressive state, which can happen in a matter of moments depending on the conditions present, such as available fuel, temperature, and ventilation.

In this stage, the fire spreads quickly and can lead to flashover, where all combustible materials in the vicinity ignite almost simultaneously. Factors contributing to this stage may include the presence of flammable materials, a substantial oxygen supply, and the end of the initial smoldering phase. Understanding this stage is crucial for fire personnel as it directly impacts strategy, tactics for fire suppression, and safety considerations.

The other descriptions do not accurately encapsulate this critical and dynamic stage. The process of ignition and the first signs of smoke pertain more to the early stages of a fire, while controlled combustion suggests a level of management and stability that does not align with the volatility associated with explosive growth.