What did the smoke column and low heat indicate to the on duty chief?

The smoke column and low heat observed by the on-duty chief typically indicate a basement or cockloft fire. When smoke is present in significant columns rising from a building without a corresponding high heat level, it suggests that the fire is located in a space where ventilation is limited and the fire may not have fully developed or spread yet.

Basement fires, in particular, can produce substantial smoke while keeping temperatures lower near the surface because of the confinement of the space and potential obstacles for heat to rise. Similarly, a cockloft fire, which occurs in the space between the roof and the ceiling of the top floor, can exhibit this smoke behavior if there is little air reaching it, causing lower heat readings.

The other scenarios like a kitchen fire, ground floor fire, or attic fire typically involve more intense heat levels and different smoke characteristics due to having more immediate fuel and ventilation options available. Therefore, the combination of a strong smoke column with low heat effectively points towards a basement or cockloft fire scenario.