Which type of thunderstorm generally produces the most intense hazard to aircraft?

• A. Single-cell thunderstorms
• B. Pulse thunderstorms
• C. Squall line thunderstorms
• D. Multicell thunderstorms

Answer: (C)

Squall-line thunderstorms generally produce the most intense hazard to aircraft because they form a long, organized line with a strong, well-defined gust front. That gust front creates widespread and severe wind shear along the edge of the line, along with powerful straight‑line winds and potential downbursts. The line can maintain strong convection over a long distance, so the exposure to turbulence, hail, heavy rain, and lightning is greater for pilots flying through or near the system.

Single-cell storms tend to be smaller and shorter-lived, so their hazards are intense but localized and brief. Pulse thunderstorms are very strong but brief and isolated, offering less sustained risk. Multicell thunderstorms contain several cells at different stages, which can produce notable turbulence and hazards, but they usually don’t present the same combination of organization and widespread wind shear as a squall line.