Thunderstorms & Lightning Safety Outdoors: Camping and Hiking Guide

Why no place outdoors is safe in a thunderstorm

A lightning flash carries an enormous current for a tiny fraction of a second, and it does not need to hit you directly to hurt you. Lightning safety guides from weather services and alpine clubs describe several ways people are injured: a direct strike; a side flash, where current jumps from a struck tree or pole to a person standing next to it; contact with something that is struck, such as a wire fence or a via-ferrata cable; and ground current, where the current spreads through the surface and through the legs of anyone standing or lying within reach.

Because of these paths, there is no spot outdoors where you are protected. A tent, a tarp, a picnic shelter, a hut without a lightning protection system, a rock overhang or a shallow cave all leave you exposed. What you can control is how likely a strike is to reach you – by timing, terrain and posture. That is why this whole article is about reducing risk step by step, and why leaving early always beats any trick on the spot.

Before you go: forecasts, warnings and a storm-proof plan

The most effective lightning protection is never being on a ridge when the storm arrives. In much of Europe and North America, summer thunderstorms build on warm, humid afternoons, and in the mountains they often develop faster than in the lowlands. Thunderstorms also come with cold fronts, which can arrive at any time of day or night. Read the forecast from your national weather service the evening before and in the morning, and check its warnings: many services publish thunderstorm warnings by district, often with timing.

Then build the day around it. Start early, put exposed sections (summits, ridges, long open plateaus, lakes) in the morning, and set a turnaround time – for example "off the ridge by 1 pm" – that you keep even if the sky still looks harmless. Mark escape routes on the map: paths that drop quickly into a valley or forest, huts, car parks and villages. The hiking time calculator shows how long a descent really takes, and the trip planning guide covers route plans and leaving details with someone at home.

Thunderstorm warning signs while hiking

Forecasts cover large areas; the storm that hits your valley shows itself in the sky. The classic sequence is described in detail in thunderstorm warning signs: small flat cumulus in the morning, clouds that grow taller than they are wide by late morning, hard, bright cauliflower towers by midday, and finally the mature cumulonimbus with a flat, spreading anvil, a dark base and thunder. Each stage is a signal to change the plan – the earlier you react, the more options you have.

Do not let the sun overhead fool you. Lightning can strike well away from the rain shaft and ahead of a storm, from what looks like a clear sky. Many weather services sum it up simply: if you can hear thunder, you are within reach of lightning. At night, flashes on the horizon without audible thunder are worth watching too – note the direction and whether they come closer.

How far away is the storm? Flash-to-bang and the 30-30 rule

Light arrives almost instantly; sound travels at roughly 343 m per second, or about 1 km in 3 seconds. Count the seconds between the flash and the thunder and divide by 3 to get the distance in kilometres (divide by 5 for miles). Count steadily ("twenty-one, twenty-two…") or use the second hand of a watch. The thunderstorm distance calculator does the maths and, with a second count a few minutes later, tells you whether the storm is approaching.

The 30-30 rule as commonly cited has two parts: under 30 seconds between flash and thunder, seek the best protection available; and wait 30 minutes after the last thunder before you return to ridges, open ground or water, because the trailing edge of a storm still produces strikes. Many weather services now prefer the stricter version – any audible thunder means act – and that is the safer habit. Use the 30-second mark as the latest point to act, not the first.

Where to go: terrain that raises or lowers your risk

Lightning tends to strike high, isolated points and anything that sticks out of its surroundings. That makes a few places outdoors clearly worse than others – and some a little less bad. Plan your escape from the worst places first.

Forest: less bad, not safe

Dense forest where the trees are of similar height spreads the risk: no single tree is an obvious target. If you are caught in woodland, move away from the tallest trees, the forest edge and lone giants, keep at least a few metres from any trunk and from low branches, and stay off ridges within the forest. Forest does not make you safe – trees are still struck and side flashes still happen – but it is better than open ground or an isolated tree.

Mountains and via ferrata

On a ridge or summit, every minute counts. Descend at once, away from the crest and from steel cables and ladders. Gullies, narrow couloirs and wet rock channels can carry current along water and are prone to rockfall in heavy rain, so do not use them as shelter. Overhangs and shallow caves are not safe either: current can jump across the opening. Huts with a lightning protection system are the right target, and alpine clubs advise planning tours so that you are there before the typical afternoon storms.

Water

If you are swimming, paddling or fishing, get out and away from the shore as soon as you hear thunder. A canoe or SUP on a lake makes you the highest point on a flat surface. Wet ground, streams and boggy meadows also carry current over wider areas.

What to do in a thunderstorm outdoors when you are caught

Sometimes the storm is faster than the plan. If you cannot reach a building or car before the count drops under 30 seconds, work through the following, in this order: lower terrain, away from isolated objects and water, metal away, group spread out – and the crouch only when a strike seems imminent.

Why feet together and why not lying down

Ground current flows through the surface outwards from a strike point. If your feet are apart, the current can use your legs as a shortcut between two points on the ground; with feet together that difference is small. Lying down does the opposite – your whole body touches the ground over its full length. The crouch also makes you lower, but it is tiring to hold and offers limited protection. Many experts stress it as a last resort, not a strategy: moving to lower, less exposed terrain is more effective as long as you still can.

Trekking poles, metal and electronics

Height and isolation matter more than metal, so a phone or a watch on your wrist makes no measurable difference – keep your phone for the emergency call. Long metal objects held up into the air, like a raised trekking pole, an ice axe on the pack or a fishing rod, make you taller and can carry current. Put them down and away. More about pole use in normal conditions is in using trekking poles.

Groups, children and dogs

The group leader decides early and clearly. Brief everyone in the morning on the turnaround time and the crouch, so nobody has to learn it in heavy rain. Keep children close enough to call to but not touching each other, and keep a dog on a lead at your side rather than letting it run onto open ground – see bushcraft with kids for more on safety rules in groups.

Thunderstorms at camp: tents, tarps, hammocks and cars

A thunderstorm at night in the tent is unsettling, and the honest answer is that a tent, tarp or hammock gives no protection from lightning. The pole material does not turn a tent into protection either way – the tent simply does nothing to stop the current – but keep metal poles away from your body, as in any storm. What protects you is choosing a site in storm season that is not a strike point and, when a severe storm is forecast, considering not camping in the forest at all.

The full method for picking a spot is in choosing a camp site for thunderstorms; for the gusts that come with storms, see camping in strong wind, and for long wet spells camping in the rain. A low, well-tensioned tarp survives storm gusts better than a high pitch, but it changes nothing about the lightning risk.

If the storm reaches your tent

If a car or building is close and the storm is still more than 30 seconds away, go there. If not, stay in the tent rather than walking around in the open: sit or crouch on your sleeping pad, off the ground as far as possible, keep away from the poles and the tent walls, and keep your boots on and ready. In a group, people in different tents are already spread out. A hammock lifts you off the ground but is hung between two trees – in a storm, leave it and crouch on a pad on the ground at a distance from the trunks.

Cars: relatively safe

A closed car, van or bus with a metal roof works like a cage: the current flows around the outside of the body into the ground. Close the windows and doors, sit back and do not touch metal parts, the door frame or the steering column. Convertibles, soft-top vehicles, plastic-bodied vehicles, motorbikes and bicycles give no protection. If you parked at the trailhead, the car is often the best destination of a storm-day descent.

First aid after a lightning strike

A person struck by lightning does not carry an electrical charge and can be touched immediately. Lightning often stops the heart or breathing, and quick help can make a real difference. The steps below follow general first aid principles; they do not replace a first aid course – an outdoor or wilderness first aid course is the best preparation.

With several casualties, first aid courses for lightning incidents usually teach to help those who are not breathing first – people who are conscious and talking are very likely to survive, while a stopped heart needs help within minutes. Afterwards, treat burns gently (cool, cover; see burns), protect the casualty from rain and wind with a jacket, a pad and an emergency blanket, because shock and wet clothing quickly lead to hypothermia. Anyone who was struck or close to a strike should see a doctor, even if they feel fine: hearing, eye, heart and nerve injuries are not always obvious at first.

After the storm: hail, flash floods and falling branches

Lightning is not the only danger a thunderstorm brings. Wait at least 30 minutes after the last thunder before you go back to exposed ground – and keep an eye on the following hazards during and after the storm.

• Hail: protect your head and neck with a rucksack or the hood of a jacket. Large hail is painful and can injure; get under a solid roof or into a car if one is close, otherwise crouch with your back to the wind.
• Flash floods: heavy storm rain can turn a dry stream bed, gully or small valley into a torrent within minutes, even if it does not rain where you are. Never camp or wait out a storm in such places, and do not cross a stream that is rising or brown with mud – wait until it falls.
• Falling branches and trees: storm gusts break dead wood and uproot shallow-rooted trees on soaked ground. Damaged trees keep falling for hours or days afterwards. Check overhead before you walk on through woodland, and read about widowmakers before choosing a camp after a storm.
• Cold: storms often bring a sharp drop in temperature. Wet clothing plus wind cools the body fast – change into dry layers early.

Lightning myths that put people at risk

Many myths contain a misunderstood grain of truth. Metal does conduct current, which is why fences and cables are dangerous – but small metal items do not "pull" lightning towards you. Low places are better than high ones – but lying flat in a wet meadow is not a good way to get low.

Storm decisions on the trail: a quick guide

Lightning safety is mostly a planning skill: start early, read the sky, know your escape routes and turn around in time. Combine it with map and compass navigation so you can find the fastest way down in poor visibility, check sunset with the daylight calculator when a storm delays you, and browse all bushcraft skills for more.