Under what conditions must safety precautions be taken if a thunderstorm warning is issued?

The correct answer emphasizes the importance of proximity and timing when it comes to thunderstorms. Safety precautions should be taken if thunderstorms are within a 10 nautical mile radius or are expected to arrive within the next 60 minutes. This threshold reflects a critical window during which the threat of severe weather, such as lightning and strong winds, is significant.

The rationale behind this guideline is that once thunderstorms are within this range, the risk of dangerous conditions, including lightning strikes, sudden gusts of wind, and heavy precipitation, increases markedly. Therefore, recognizing and responding to a warning based on this distance and time frame allows for necessary safety measures to be implemented effectively, ensuring the safety of personnel and operations.

While ceasing outdoor operations, seeking secure indoor locations, and grounding equipment are important safety measures in severe weather, the urgency determined by the specified distance and expected time frame is crucial in the initial response to a thunderstorm warning. This approach allows for an organized and timely reaction to ensure everyone's safety before conditions become hazardous.