What does the term "drifting snow" refer to in METAR coding?

The term "drifting snow" in METAR coding is specifically represented by the code "DRSN." This code is used to describe snow that is being blown around by the wind, which can significantly impact visibility and pavement conditions. The "DR" prefix stands for "drifting," while "SN" signifies "snow." This distinction is essential for pilots and meteorologists as it conveys important information about current weather conditions that could affect flight operations.

The other codes pertain to snow but do not specifically indicate that the snow is drifting. For instance, "DS" simply indicates snowfall without reference to the drifting aspect, "DSN" is not a standard METAR code, and "SN" signifies snow in general. Therefore, "DRSN" effectively communicates the specific condition of drifting snow, making it the correct response in this context.