What does a white cloud typically indicate when observed during a fire?

A white cloud observed during a fire typically indicates steam. Steam is produced when water is heated to its boiling point and transforms into vapor; this can occur in the intense heat of a fire when water from firefighting efforts or moisture in the materials being burned is vaporized. The appearance of a white cloud suggests a significant amount of heat energy is present, causing rapid evaporation and the formation of steam, which may rise and spread in the air.

In contrast, smoke, gas, and fumes would generally not present as a white cloud. Smoke is often darker and can vary in color depending on the materials burning. Gases released during combustion can be invisible or may have different colors depending on the chemical makeup, while fumes may be associated with specific volatile substances and can also have varied appearances. Therefore, when witnessing a white cloud in the context of a fire scene, it's most likely indicative of steam generated from heated water.