Which observation from Charlie division signaled potential issues regarding the fire scope?

A band of fire where the roof met the wall can indicate serious structural issues and the potential for significant fire spread. This observation suggests that there may be a failure in the building's integrity, which can allow flames to move into concealed spaces or result in structural collapse. A visible band of fire in this area is particularly concerning as it may compromise not only the effectiveness of firefighting efforts but also the safety of personnel operating within the structure. Identifying such symptoms is crucial for assessing the fire's behavior and devising an appropriate tactical response.

The other observations, although noteworthy, do not directly indicate the same level of potential structural compromise or fire spread. For example, smoke color from the west wing may inform about the materials burning, and water pressure variations could indicate pump issues or line obstructions. No alarms being triggered suggests potential system failures but does not directly inform about immediate fire behavior or structural risks. In contrast, the observation of fire at the junction of the roof and wall presents an urgent sign of escalating danger that requires immediate attention from firefighting personnel.