What occurs during the ignition phase of a fire?

During the ignition phase of a fire, the fire tetrahedron's four elements—fuel, heat, oxygen, and a chemical reaction—come together to initiate combustion. This phase is crucial because it marks the moment when a fire can begin to grow and sustain itself. Fuel is ignited by a heat source, with adequate oxygen present in the environment, leading to a self-perpetuating chemical reaction.

In this context, the other options do not accurately describe the ignition phase. While the fire plume does begin to form as a fire develops, this is a later stage that occurs after ignition has already taken place. The concept of a fire suppressing itself does not apply during the ignition phase, as there is a need for the fire to establish itself first. Similarly, removing the heat source is an action that would lead to extinguishment rather than ignition.