Which of the following phenomena can be reported with an intensity qualifier?

Drizzle can be reported with an intensity qualifier because intensity qualifiers are used in aviation weather reports to describe the severity of precipitation. In this context, drizzle can be categorized as light or heavy depending on the rate at which it falls. This provides pilots and meteorologists with crucial information about weather conditions that may affect visibility and aircraft performance.

When it comes to fog, while it can significantly impact visibility, it is generally reported without an intensity qualifier. Instead, fog is simply described in terms of its presence and the visibility it creates. Similarly, small hail and smoke do not use intensity qualifiers; these phenomena are reported based on their occurrence and characteristics but lack the classification system that intensity qualifiers provide for precipitation. Thus, drizzle is unique among the options given, as it allows for a clearer understanding of the potential impact it may have on flight operations when classified by intensity.