What does clean, unsmoked window glass found outside a burning structure possibly indicate?

The presence of clean, unsmoked window glass outside a burning structure is a significant observation that may suggest that an explosion occurred before or during the fire. In the context of a fire scene, smoke and soot typically accumulate on glass surfaces as a result of combustion. Therefore, if glass appears clean and free of smoke residue, it raises questions about the conditions prior to the fire.

An explosion can create a rapid release of gases and can forcefully expel windows from their frames, resulting in glass shattering or being blown outward. The absence of smoke on the glass could indicate that the explosion occurred in an environment that was not yet fully engulfed in smoke or in which the flames had not yet reached the window area extensively. This suggests an event that preceded the fire's main development, linking the clean glass to a potential explosion event, highlighting it as an important indicator for investigating the circumstances leading to the fire.