Updated: July 2026
Mountain weather can change in minutes. One moment you’re hiking toward a sunny alpine pass, and the next you’re pulling on a rain jacket as dark clouds gather and thunder echoes across the valley.
Summers with stretches of intense heat often bring more afternoon thunderstorm build-ups. Warm air rising off sunbaked valleys and slopes helps clouds develop quickly, so clear, sunny mornings can give way to dark clouds, thunder, and lightning by early afternoon. This is worth watching for on any hike, but especially during a heat wave, when the pattern becomes more frequent and predictable.
The good news is that most lightning incidents are preventable. Starting early, watching the sky, and getting off exposed terrain before storms develop are some of the simplest, and most effective, ways to stay safe.
Five Rules to Follow During a Lightning Storm
Follow these five guidelines whenever you’re hiking in the mountains:
- Plan ahead to avoid or at least to mitigate the risk of thunderstorms.
- Move to safer terrain if thunderstorms approach (Move to lower elevation, away from exposed summits or ridgetops, and away from tall solitary objects and standing water.)
- If you’re stuck on a high, exposed area, then crouch and minimize contact with the ground.
- Set trekking poles aside and avoid holding long metal objects.
- If you’re hiking in a group, spread out about 20 feet apart.
How Lightning Works
Lightning forms when rising warm air and ice particles inside storm clouds create large electrical charges. Eventually that energy is released between the cloud and the ground. Tall, isolated objects, such as lone trees, ridgelines, or mountain summits, are more likely to be struck, which is why exposed terrain is especially dangerous during a thunderstorm. While being struck by lightning is uncommon, the consequences can be severe. Fortunately, most lightning injuries can be prevented through good planning and by leaving exposed terrain as soon as storms begin to build.
Why Heat Waves Increase Thunderstorm Risk
Hot weather and mountain thunderstorms often go hand in hand. As the ground heats during the day, warm air rises rapidly and collides with cooler air higher in the atmosphere. That instability fuels the towering cumulonimbus clouds responsible for lightning and thunderstorms. In the Alps and many other mountain ranges, this often creates a familiar pattern: beautiful mornings followed by rapidly developing afternoon storms. During summer months, and especially during heat waves, follow the mountain hiker’s rule to “start early and descend early” becomes more important than ever.
If you’re traveling with Ryder-Walker, simply tap the weather icon in your Vamoos app each morning to check the day’s forecast before heading out.
Plan Ahead
The safest way to deal with lightning is to avoid it altogether. Check the forecast before leaving, understand the local weather pattern, and aim to cross exposed ridges, passes, and summits early in the day before thunderstorms typically develop. If storms are forecast, choose a lower-elevation route or shorten your hike. Perhaps the hardest lesson for hikers to learn is knowing when to turn around. No summit is worth pushing into a thunderstorm.
Always carry warm, waterproof layers, including base layers, rain jacket and pants, hat, and waterproof gloves. Even in summer, heavy rain, wind, and hail can quickly lead to hypothermia at higher elevations.
Move to Safer Terrain
You’ve probably heard the saying, “When thunder roars, go indoors.”
If you’re already on the trail hiking and no shelter is available, immediately leave exposed ridges, summits, and open slopes. Descend toward lower ground and look for a dense stand of shorter trees or lower terrain. Avoid isolated trees, cliff edges, open meadows, and standing water.
If You’re Trapped Above Treeline
If lightning is imminent, especially if your hair begins standing on end, take the lightning position immediately.
Do not lie down.
Rather, get in the lightning position (see illustration)
- Keep your feet together.
- Stay low in a crouched position.
- Keep your hands off the ground.
- Balance on the balls of your feet if possible.
- Cover your ears with your hands.
This position won’t prevent a lightning strike, but it reduces the amount of ground current that can travel through your body.
What about trekking poles?
If you have trekking poles, place them a short distance away. While small metal objects like phones, watches, or jewelry do not attract lightning, there’s no reason to continue holding long conductive objects during a storm. Your priority should always be reaching safer terrain, not worrying about removing every metal item you’re carrying.
Spread Out
If you’re hiking with others, spread out by roughly 20 feet. The goal isn’t to reduce the chance of lightning striking nearby, it’s to reduce the chance that everyone in the group is injured by the same strike. Stay close enough that you can still communicate and quickly assist someone if needed.
If lightning strikes a person, they do not retain an electrical charge. It is safe to provide first aid or CPR immediately while another member of the group contacts emergency services.
Wait at least 30 minutes after the last clap of thunder before returning to exposed terrain.
Hiking with a Guide Takes the Guesswork Out
One advantage of hiking with an experienced guide is that weather decisions are made long before storms become dangerous.
Our guides monitor local forecasts, watch developing conditions throughout the day, and adjust departure times, pacing, or turnaround points to keep groups off exposed terrain whenever possible. That’s especially valuable during periods of hot weather, when afternoon thunderstorms can develop quickly.
One Final Thought
Mountain weather deserves respect, but it shouldn’t keep you from exploring. With an early start, a close eye on the forecast, and the willingness to turn around when conditions change, you’ll be well prepared to enjoy the mountains safely.
Looking for more trail advice? Read our blog, Wander Wise: A Guide to Safety on the Trails and Hiking Etiquette, for additional tips on hiking safely and responsibly.
By Sarah Lavender Smith
Sarah Lavender Smith is a running coach, author and longtime trail runner who has competed in some of North America’s toughest ultramarathons. When not running or hiking, she often can be found on trails riding her horse. Sarah lives in Telluride with her husband and two kids. One of her proudest accomplishments is traveling nomadically around the world for a year with her family visiting five continents.
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