What causes secondary fires to occur?

Secondary fires occur due to various factors that can exacerbate an initial fire situation. The correct answer, indicating that all the options contribute to the occurrence of secondary fires, underscores the complexity of fire spread and the conditions that foster it.

Reduction in humidity can increase the combustibility of materials in the environment, making them more likely to ignite and sustain a fire. Dry air removes moisture from fuels, which can lead to quicker ignition and a greater tendency for fires to spread.

The availability of additional fuel is critical. If a fire has access to more combustible materials—such as grassy fields, wooden structures, or flammable liquids—it can grow significantly larger and create new ignition sources, leading to the inception of secondary fires.

High temperatures in the area can also play a crucial role. Elevated temperatures can lead to thermal radiation effects, causing nearby materials to reach their ignition point. This heat can not only spread existing fires but can initiate new ones in adjacent areas.

These factors combined illustrate why it is accurate to conclude that various conditions work together to cause secondary fires, highlighting the need for comprehensive fire management strategies.