Definition
A sudden change in wind speed and/or direction over a short distance occurring at or below 2,000 feet above ground level. It can produce rapid gains or losses of airspeed and abrupt vertical movement of the aircraft, and is most hazardous during takeoff, initial climb, approach, and landing.
Plain English
A fast change in the wind close to the ground, where the wind direction or strength shifts sharply over a short distance. Because it happens low down, the aircraft has little altitude to recover if it loses lift or airspeed.
Context Anchor
Pilots encounter this term in weather briefings, airport weather reports, approach planning, and training on takeoffs and landings in gusty or stormy conditions.
Derivation
‘Shear’ comes from the Old English ‘sceran,’ meaning to cut or divide. In meteorology, it describes air masses moving differently right next to each other, as if the wind has been ‘cut’ into layers. ‘Low-level’ simply marks where it happens: near the ground.
Why Pilots Care
It can cause abrupt loss of airspeed and altitude during critical phases of flight, increasing the risk of stall or runway excursion if not promptly corrected.
Grounding Statement
Picture flying into a strong headwind on final approach, then having that headwind disappear in a second — the aircraft suddenly feels slow and starts to sink, with little room below to recover.
Intuition Check
Do not read “low-level” as “low danger” or “mild.” Here it means low altitude, close to the ground, where wind changes leave little room to recover.
Example Sentence 1
The ATIS reported low-level wind shear on final, so the crew briefed a go-around in case the airspeed dropped during the approach.
Example Sentence 2
Pre-takeoff briefing included a wind-shear escape maneuver because the ATIS reported low-level wind shear from an approaching cold front.