Definition 1 of 2
Definition
Frozen precipitation made up of ice crystals that form directly from water vapor in clouds at temperatures at or below freezing. On an aircraft, accumulated snow adds weight, disrupts airflow over the wings, and can mask underlying ice or frost — all of which degrade lift and increase stall speed.
Plain English
Frozen flakes of ice that fall from clouds. On an airplane, even a thin layer changes how the wings work and makes the airplane more likely to stall.
Context Anchor
In the stalls chapter, snow is most important as contamination on the wing or tail that can change how air flows over the aircraft.
Derivation
Snow comes from an old English word meaning the same thing: frozen precipitation. The origin is simple, but it helps keep the aviation meaning tied to the physical substance: frozen water that can collect where the airplane needs clean airflow.
Why Pilots Care
Snow on the wings increases stall speed and can cause an earlier-than-expected stall with reduced control effectiveness.
Grounding Statement
Picture a normally smooth wing with a thin uneven layer of snow on it; the air can no longer flow over that wing the way the aircraft was designed for.
Intuition Check
Do not assume snow only matters when it is deep or heavy. In aviation, even a light layer of snow on a lifting surface can be unsafe.
Example Sentence 1
Before taxiing, the pilot brushed all the snow off the wings and tail to make sure the aircraft was clean for takeoff.
Example Sentence 2
A light coating of snow on the leading edge raised the stall speed enough to surprise the pilot on rotation.