Lightning safety outdoors

Lightning kills around 20 to 30 people in the US in a typical year and injures hundreds more, many left with lasting neurological damage. The deaths cluster in exactly the places readers of this blog spend time: open water, ridgelines, ballfields, and trails. The uncomfortable core fact, straight from NOAA, is that no place outside is safe near a thunderstorm. Everything below is about managing risk when you cannot reach real shelter, and about arranging your day so you rarely have to.

Know your distance: the flash-to-bang count

Count the seconds between the lightning flash and its thunder, then divide by five for miles (sound covers about a mile every five seconds). Thirty seconds means six miles, and six miles is inside strike range; bolts routinely hit that far from the parent storm, ahead of any rain.

That is the basis of the 30-30 rule: when flash-to-bang drops to 30 seconds or less, get to shelter, and stay there until 30 minutes after the last thunder you hear. The back end matters as much as the front; a large share of casualties happen after people head back out while the storm is “basically over.” If you can hear thunder at all, you are close enough to be struck.

Real shelter, and the impostors

Two things count as safe: a substantial enclosed building with wiring and plumbing, or a fully enclosed metal-topped vehicle with the windows up. The car works not because of the tires but because the metal body routes current around the occupants. Inside either one, stay off corded electronics and plumbing until the storm passes.

Things that do not count: tents (a tent pole is a fine lightning rod with fabric on it), picnic pavilions, rain flies, cave mouths and rock overhangs (current jumps the gap right where you are crouched), and isolated trees, which are involved in a large share of strike casualties.

Caught out with no shelter

If the storm catches you in the open, you are reducing odds, not eliminating them:

• Get off ridgelines, peaks, and open water immediately. Descend. Elevation is the biggest single factor you control, and this is why mountain travelers plan summits for morning; afternoon is thunderstorm shift.
• Avoid the tallest objects around and anything long and conductive: fences, power lines, wet ropes, metal trekking poles (drop them a distance away).
• Prefer low ground, uniform low cover like young trees or brush, or a dry ravine (mind flash flooding).
• Spread your group out, 50 to 100 feet between people, so a single strike cannot injure everyone and the unhurt can help the hurt.
• As a last resort during immediate danger (hair standing up, crackling, a nearby strike), use the lightning position: crouch on the balls of your feet, feet together, head down, hands off the ground. Be clear-eyed: agencies now teach this as a final measure only, with limited evidence it helps much. Moving toward safety early beats crouching well.

After a strike: act fast, and get trained

Strike victims do not carry charge; they are immediately safe to touch. Many die from cardiac arrest that prompt CPR can reverse, and lightning victims have better resuscitation odds than most cardiac arrest cases. Call for help, start CPR if there is no pulse or breathing, use an AED if one exists within reach, and treat for other injuries. A blog post is not medical training: a CPR certification course costs a few hours and an evening, and lightning response is one of its clearest use cases. Book one.

The real skill is scheduling

Nearly every backcountry lightning emergency was visible in the morning: a forecast mentioning afternoon storms, cumulus towering by 10 a.m., a route plan with the exposed section at 3 p.m. Learning basic weather signs and moving your summit or crossing to before noon eliminates more risk than any crouch ever will.

Your next step

Memorize two numbers this week: 30 seconds flash-to-bang means take shelter, and 30 minutes after the last thunder means stay there. Then check the calendar for a local CPR course and put your name on it. Both are free to cheap, and both outperform every piece of gear in the pack when the sky goes loud.