Definition
Describes liquid water that remains in liquid form at temperatures below 0 °C (32 °F), the point at which it would normally freeze. Supercooled water droplets are unstable and will freeze on contact with an aircraft surface, producing structural icing.
Plain English
Water droplets that are still liquid even though they are colder than freezing. They turn to ice the instant they hit something solid, like an aircraft wing.
Context Anchor
Seen in icing discussions, weather reports, and training about flying in clouds or rain near or below freezing temperatures.
Derivation
From 'super-' (Latin, meaning 'beyond' or 'above') and 'cooled.' Here 'super' does not mean 'great' or 'excellent' — it means 'beyond' the normal point. So 'supercooled' literally means 'cooled beyond' the usual freezing temperature without actually freezing.
Why Pilots Care
Supercooled droplets freeze instantly on contact with an aircraft, producing rapid and hazardous ice accumulation on wings and control surfaces.
Grounding Statement
Picture pure water in a clean cloud at -10 °C. It has nothing to freeze onto, so it stays liquid — until your wing arrives, and then it freezes instantly on contact.
Intuition Check
Supercooled does not simply mean “very cold.” It means liquid water that is below freezing temperature but has not frozen yet.
Example Sentence 1
Flying through a layer of supercooled droplets, the pilot saw clear ice forming rapidly on the leading edge of the wing.
Example Sentence 2
Before takeoff the pilot checked for the possibility of supercooled precipitation in the forecast.