What phenomenon is described as black smoke that appears whitish within a few feet of a vent opening?

The phenomenon described as black smoke appearing whitish within a few feet of a vent opening is known as "white ghost." This occurs due to the condensation of water vapor when hot gases mix with cooler air at the vent. As the black smoke, which consists of particulate matter and other combustion products, exits the vent and interacts with the cooler air, the moisture in the smoke condenses. This results in a white, ghostly appearance close to the vent.

In contrast, ice fog refers to very fine ice crystals that can form in extremely cold conditions, while cool mist generally describes a moisture-laden air that does not pertain to the behavior of smoke. Cold vaporization would typically refer to the process where a liquid converts to vapor at lower temperatures, which is not relevant in the context of smoke behavior. Understanding this phenomenon is essential for recognizing visual cues during fire incidents, which can aid in assessing fire conditions and making tactical decisions.