What occurs during the flashover stage of a fire?

The flashover stage of a fire is characterized by a critical moment when all combustible materials in the room reach their ignition temperature almost simultaneously. This phenomenon occurs because the heat produced by the fire raises the temperature of the surrounding materials, creating a situation where flames spread quickly and dramatically.

In flashover, the radiant heat from the flames heats nearby surfaces, and when these surfaces reach their ignition temperature, they ignite. This rapid transition can lead to a quick escalation of the fire, resulting in a fully involved room in a matter of moments. The synchronicity of ignition among various surfaces is a key aspect of flashover, illustrating how it facilitates the rapid progression of fire.

The other options highlight factors that are either not characteristic of the flashover stage or are concepts related to different stages of a fire's growth and behavior. For example, while an increase in fuel availability is an essential factor in fire dynamics, flashover specifically refers to the simultaneous ignition of those fuels, rather than an increase in their availability. Similarly, oxygen levels tend to decrease as a fire grows and consumes available oxygen, but in flashover, there is actually a spike in combustion activity before potential depletion occurs. Understanding the dynamics of flashover is critical for fire investigators, as it impacts