What is a key indicator of a potential backdraft situation?

In understanding backdraft situations, option B highlights a key indicator. High smoke production without visible flames often suggests that there is excess fuel remaining in the environment and a limited supply of oxygen. This combination can create dangerous conditions, as the unburned fuel can lead to an explosive situation if the right ignition sources and oxygen are introduced.

Additionally, smoke curling back into the structure, as mentioned in option C, also indicates a potential backdraft. This phenomenon typically occurs when there is a lack of oxygen in the environment, and smoke is being drawn back into the building due to an existing vacuum or negative pressure, further heightening the risk of a backdraft.

Furthermore, a sudden drop in temperature around the structure, as noted in option D, can be indicative of fire conditions changing, which can also signal a potential for backdraft or flashover.

Understanding these indicators is crucial for firefighting strategies and ensuring the safety of both firefighters and civilians in fire situations.