Safety Guide
Lightning Safety Guide: What to Do During Summer Thunderstorms
Important thunderstorm protocols and the science of lightning safety to avoid strikes.
Last Updated
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Written by WeatherCA Staff
The 30-30 Rule
Lightning is one of the leading weather-related causes of injury in Canada. To protect yourself, always remember the 30-30 rule:
- Count: If you see lightning, count the seconds until you hear thunder. If that time is 30 seconds or less, the storm is close enough to strike you. Immediately seek shelter.
- Wait: After the last flash of lightning or rumble of thunder, wait at least 30 minutes before going back outside.
Safe Shelters vs. Unsafe Spots
If caught outdoors during a thunderstorm, seek shelter in a fully enclosed building with wiring and plumbing, or a metal-topped vehicle. Avoid: open structures (pavilions, tents), tall isolated objects (trees, poles), and bodies of water.
