Definition
In a METAR, DR is a descriptor indicating that a weather phenomenon (such as snow, sand, or dust) is being blown by the wind at less than six feet above the ground. It is paired with the phenomenon being described, for example DRSN (low drifting snow) or DRSA (low drifting sand).
Plain English
Wind is pushing loose material like snow, sand, or dust along the ground, but only low down — below about eye level. Anything higher than that is not affected.
Context Anchor
Seen in METAR present-weather codes, usually attached to snow, dust, or sand, such as low drifting snow near an airport surface.
Derivation
From the ordinary English word 'drift,' meaning to be carried along by a current of air or water. The 'low' qualifier specifies that the drifting is happening close to the surface — below six feet — to distinguish it from 'blowing' (BL), which means the same material is being lifted higher into the air.
Why Pilots Care
Low drifting can reduce surface visibility on runways during takeoff and landing, affecting decisions about operations in windy conditions.
Grounding Statement
Picture wind sliding loose snow across the runway like a thin moving sheet close to the pavement.
Intuition Check
Low drifting does not mean the weather is happening high in the sky or that all visibility is poor. In this code, low means the moving snow, dust, or sand is staying below about 6 feet above the ground.
Example Sentence 1
The METAR included DRSN, warning the pilot that drifting snow was reducing the visibility of runway edge markings during taxi.
Example Sentence 2
Strong winds caused DR DU along the taxiway, but conditions remained clear above six feet.