What are the warning signs of structural collapse during a fire?

Heavy smoke and loud creaking sounds are significant indicators that a structure may be on the brink of collapse during a fire. Heavy smoke suggests a significant fire is occurring within the structure, indicating that materials are burning and weakening the structural integrity. As the fire progresses, the heat can lead to materials like wood and metal losing their strength, resulting in creaking noises as they begin to buckle or fail. These audible signs alert firefighters to the potential danger of a collapse, allowing them to make crucial decisions regarding the safety of personnel and the approach to combating the fire.

While other signs can also indicate hazardous conditions, they do not specifically correlate with the immediate risk of structural collapse as effectively as heavy smoke and creaking sounds. For instance, flickering lights might signal electrical issues but do not directly indicate structural safety. Similarly, the presence of flames or water accumulation does not necessarily relate to the likelihood of collapse, nor do unusual smells or broken glass, which can occur in various scenarios without indicating a compromised structure. Thus, heavy smoke and loud creaking sounds serve as more direct warnings of potential collapse.