FAA Flight Instructor Airplane (FIA)Weather and Weather ServicesMedium
A pilot asks a flight instructor how large hailstones develop inside a thunderstorm. Which explanation is correct?
- AStrong updrafts repeatedly carry precipitation particles above and below the freezing level, adding layers of ice with each cycle
- BPrecipitation falls once through a single freezing layer and immediately reaches the ground as hail
- CHail forms only during the dissipating stage when downdrafts dominate the entire cell
- DSupercooled water droplets instantly freeze into large stones upon contact with the aircraft's leading edge
Show answer & explanationAnswer & explanation
Correct answer: A. Strong updrafts repeatedly carry precipitation particles above and below the freezing level, adding layers of ice with each cycle
Hail forms in the mature stage of a thunderstorm when strong updrafts carry ice particles up through supercooled cloud layers, then downdrafts or gravity pull them down, repeating the cycle and adding successive layers of ice until the stone becomes too heavy for the updraft to support, at which point it falls.
Why the other options are wrong
- B. A single pass through a freezing layer produces small ice pellets or graupel, not large layered hailstones.
- C. Hail formation requires strong updrafts, which are strongest in the mature stage, not the dissipating stage.
- D. This describes structural icing on an aircraft, not the process of hail formation within a cloud.
Hail Formation
Hail forms when strong thunderstorm updrafts repeatedly cycle ice particles through supercooled layers, adding layers of ice until the stone falls.
- Requires strong updrafts found in the mature stage
- Larger hail indicates stronger updrafts
- Layered structure of a hailstone reflects multiple freeze cycles
Memory trick: Hail is built like an onion—layer by layer riding the elevator up and down