What is the guideline known as for lightning safety?

The guideline known for lightning safety is referred to as the 30/30 rule. This rule indicates that individuals should seek shelter when they see lightning within 30 seconds, and they should remain sheltered for 30 minutes after the last clap of thunder. The rationale behind this guideline is based on the observation that lightning can strike several miles away from the storm itself and that the storm is often still dangerous even after the immediate lightning activity has ceased.

The 30-second count is a way to gauge how close the storm is: if the count is less than 30 seconds, the storm is within striking distance, emphasizing the importance of immediate action. Similarly, the 30-minute wait after thunder ensures that the storm has moved on and that it is safe to exit the shelter. This approach is crucial for safety in outdoor environments, particularly in situations like concerts, festivals, and other events where large groups of people are present.