The 30/30 rule of lightning could save your life

Stunning lightning show in North Vancouver, BC, Canada by katiemills.

The next time you’re caught outside in an electrical storm, remember Environment Canada’s “30/30 Rule.” It just might save your life.

Here’s how it works: count the seconds between the flash of a lightning strike and the next boom of thunder. If it’s under 30 seconds, the storm is less than 10 kilometres away and, according to Environment Canada, there is an 80-percent chance the next strike will occur within that 10-kilometre radius.

Now is the time to take shelter: quickly! Get inside a house, if possible, into an all-metal vehicle, or move to a low-lying area. Stay put. Once you’ve heard the last peal of thunder, wait for 30 minutes before leaving your shelter.


Unfortunately, there was little shelter from the storm for the climbers in our Winter 2007 cover story, “Terror on Bugaboo Spire.” The events that transpired when a lightning storm trapped the foursome near the summit of the treacherous, 3,176-metre granite peak in the Kootenay’s Purcell Mountains are almost beyond belief.

Chances are, once you’ve read about the adventure in our Winter 2007 issue, you’ll never forget the “30/30 Rule.” But just in case, the good folks at Sport Research Intelligence and Environment Canada have produced a downloadable, wallet-sized 30/30 card.

For more information about the dangers of lightning storms, visit Environment Canada’s website.


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