What to do
- 1Before the trip: check the forecast; if storms are likely, change the plan — start early, pick lower routes, or postpone.
- 2Watch the sky: building cumulus or cumulonimbus means act now.
- 3At first thunder, go to safe shelter — a substantial building or a hard-topped vehicle with windows up. Don't wait for rain or a close strike.
- 4Get off exposed terrain fast — descend from ridges and peaks, leave open fields and water, move away from lone tall trees and metal.
- 5If truly caught out: find lower ground (not a gully or streambed), spread the group apart, minimize your contact with the ground, and do not lie flat.
- 6Wait at least 30 minutes after the last thunder before resuming.
- 7If someone is struck: it's safe to touch them (they carry no charge); call for emergency help and begin CPR immediately — cardiac arrest is the main cause of death.
Remember it as
When Thunder Roars, Go Indoors.
When to use it
- Any outdoor activity in thunderstorm season — hiking, climbing, aquatics, field sports.
- Exposed terrain (ridgelines, summits, open water, big fields), where lightning risk is highest.
- Aquatics and swimming, where getting everyone out of the water at the first thunder is the rule.
Common mistakes & safety
- The only safe places are a substantial building or a hard-topped vehicle. Tents, dining flies, and picnic shelters do NOT protect you — get to real shelter.
- Hear thunder → go in; no outdoor spot is safe. Don't gamble that the storm is "far away" — if you can hear it, you can be struck.
- Wait 30 minutes after the last thunder. Most people are struck before or after the rain, when they think it's over.
- Off high ground, away from lone trees, water, and metal. These attract or conduct strikes — a lone tall tree is one of the most dangerous places to shelter.
- Don't lie flat. Lying flat increases exposure to ground current — make yourself small but keep contact minimal.
- A struck person is safe to touch and needs help now — begin CPR and call for help immediately. And get out of the water at the first thunder.
Going deeper
- "When Thunder Roars, Go Indoors." The whole rule in five words — if you can hear it, you can be hit; go to real shelter.
- The 30-minute rule saves the people who think it's over. Strikes happen at the edges of a storm; waiting 30 minutes after the last thunder covers the deadliest window.
- A tent is not shelter. The most dangerous false comfort — get to a building or a hard-topped car, not a tent or a rain fly.
Official source
Lightning safety tips — National Weather Service →This is life-safety guidance — follow current NWS and Red Cross guidance, and treat a strike victim as a medical emergency.