When flying around thunderstorms, what distances must you keep in mind?

• A. Maintain 10 nm distance from all storms.
• B. No flying between thunderstorms less than 40 nm apart.
• C. Avoid the downwind side of the Anvil.
• D. No flying within 20 nm of the edge of a thunderstorm.

Answer: (D)

Thunderstorms create hazardous conditions not only inside the storm but around its edges. The safest protection is to stay at least 20 nautical miles away from the edge of any thunderstorm. This buffer helps you avoid the strongest turbulence, wind shear, gust fronts, hail, and lightning that can extend well beyond the visible cloud, giving you room to maneuver safely if the storm shifts. The other distances don’t align with standard weather avoidance guidance: 10 nm is too close to the storm’s edge for safe margins; 40 nm between storms isn’t a guaranteed protection because hazards can extend beyond that separation; and avoiding only the downwind side of the anvil misses the fact that dangerous conditions can be present on or near the storm’s edge in various directions.