What is rollover (flameover) best described as?

Rollover, also known as flameover, occurs when hot gases accumulate in the upper levels of a room and eventually ignite. This phenomenon typically happens in a compartment during a fire where the temperature of the gases surpasses the ignition point. When the combustible gases reach this threshold, they spontaneously ignite, resulting in flames spreading across the ceiling or upper walls of the room.

This event is critical for firefighters to understand because it signifies a significant danger; the ignition of these gases can rapidly change the dynamics of a fire, potentially leading to flashover. Recognizing the signs of rollover can help firefighters assess the conditions within a space and make informed decisions on how to attack the fire or protect themselves from potential hazards. Other choices do not accurately capture the essence of rollover; they refer to different aspects of fire behavior or dynamics.