FAA Instrument Rating Airplane (IRA)Weather and Weather ServicesMedium
A pilot receives a PIREP reporting large hail beneath a rapidly building cumulonimbus cloud. This report is most indicative of which condition within the storm?
- AA weakening storm in its dissipating stage
- BA stable air mass with minimal vertical development
- CStrong updrafts capable of suspending large water/ice particles
- DPredominantly stratiform precipitation with light turbulence
Show answer & explanationAnswer & explanation
Correct answer: C. Strong updrafts capable of suspending large water/ice particles
Large hail forms when strong updrafts repeatedly carry water droplets above the freezing level, allowing layers of ice to accumulate before the hailstone becomes too heavy to be supported. The presence of large hail therefore indicates very strong updrafts and severe turbulence potential.
Why the other options are wrong
- A. Dissipating storms have weakening downdrafts and are unlikely to produce large hail.
- B. Stable air mass does not support the vertical development needed for hail formation.
- D. Stratiform clouds lack the strong vertical currents necessary to produce large hail.
Hail Formation
Hail forms in strong thunderstorm updrafts that repeatedly loft water droplets above the freezing level, building ice layers until the stone falls.
- Requires strong, sustained updrafts
- Larger hail = stronger updrafts
- Associated with severe turbulence
Memory trick: Big hail = big updraft.