Lightning: If You Can Hear Thunder, Change Your Plan

Mountain weather punishes the "summit first, weather later" mindset. Thunder is not background noise — it is the signal to change the plan.

Change Plans the Moment You Notice

• Distant thunder, cumulonimbus building fast, darkening cloud bases, a sudden wind shift, a temperature drop, or the first drops of rain or hail.
• The shorter the gap between flash and thunder, the closer the storm. Don't wait until you "see lightning" to act.

Where to Go

• Best options: a substantial building with plumbing and wiring, or a closed hard-topped metal vehicle with the windows up.
• Avoid: summits, ridges, open meadows, lakeshores, isolated single trees, shallow rock alcoves, and pavilions. And tents — a tent is not lightning protection.
• Stay put until at least 30 minutes after the last thunder.

Caught in the Open — Last Resort

• Drop elevation fast and get away from ridges, summits, water, lone trees, metal fences, and power lines.
• Don't lie flat. Crouch on the balls of your feet with your feet together and your head low — this reduces risk; it is not safety.
• Spread the group out so a single strike can't take multiple people.
• Don't shelter in shallow caves or under rock overhangs — the current can travel along the rock face.

Plan Around the Window, Not Just the Rain

• Before the trip, read thunderstorm probability, wind, temperature drop, visibility, and precipitation timing. Treat "afternoon thunderstorms" as a hard design constraint on the route.
• For long routes and exposed sections: start early, cross the pass early, and be off the ridge by afternoon. Mark storm bailout points on the map.
• When the window is uncertain, change the route or the date. "We came all this way" is a bad reason to gamble.

Common Mistakes

• Waiting at the pass or summit for "the rain to stop."
• Huddling under a lone big tree or a rock overhang.
• Treating a tent as a refuge.
• Checking only the temperature while ignoring wind and storms.