Which of the following is an indicator of potential structural collapse?

Creaking noises serve as a significant indicator of potential structural collapse due to the mechanical stress and instability they often signify within a building. When a structure is experiencing substantial strain, particularly from factors such as overloading or damage, it may begin to warp or move, leading to these audible sounds. These noises suggest that the integrity of the structure is compromised, potentially signaling that a failure could occur if the situation is not addressed promptly.

Conversely, high wind conditions, dense smoke, and large crowds nearby can contribute to hazardous situations in various ways but do not directly indicate structural integrity issues. High winds may affect buildings, particularly temporary or makeshift structures, but do not inherently signify a collapse. Dense smoke typically signals fire but does not automatically suggest the risk of structural failure unless coupled with other indicators. Large crowds nearby present a different type of concern related to crowd management and safety rather than a specific indicator of structural integrity.