Which of the following is a hazard associated with thunderstorms?

Strong updrafts and downdrafts are indeed a significant hazard associated with thunderstorms. These vertical air movements can lead to severe turbulence, making flight particularly dangerous. Updrafts can lift an aircraft rapidly and unexpectedly, while downdrafts can force an aircraft downwards, potentially leading to loss of control if not managed properly. Understanding these dynamics is crucial for pilots and those involved in aviation, as they require careful navigation strategies to avoid dangerous weather conditions.

In contrast, visible navigation lights, clear skies, and quiet flight conditions do not represent hazards; they are indications of favorable flying situations. Clear skies and quiet conditions suggest stable weather, while visible navigation lights are intended to enhance visibility for safe navigation rather than indicate risky weather phenomena.