Caught in a Thunderstorm on a Walk: When to Turn Back and Where to Wait It Out

Thunder is a signal to change your plans

You don’t need to calculate how far away a storm is before going for a walk: if you hear thunder, head for safe shelter right away. Don’t wait for the rain to start, stop for a photo, or try to finish your loop. The U.S. National Weather Service (NWS) recommends taking shelter in a substantial building or an enclosed metal vehicle and staying there for at least 30 minutes after the last thunder. This rule is a simple guide for an ordinary walk, too.

These figures don’t mean that the risk disappears after 30 minutes in all weather, or that lightning will definitely strike 16 km away. They’re reminders of practical safety guidelines: the NWS advises waiting 30 minutes, and the CDC warns that lightning can strike about 16 km from the rain. The number 157 refers to reported fatal cases; it does not show the likelihood of being struck under a tree.

If you hear thunder, head for shelter. Don’t try to work out how close the storm is, and don’t use rain as your only sign of danger. This is the NWS safety rule: if you can hear thunder, the risk is high enough to seek shelter immediately.

Before you head out: check more than the route

Check the forecast for the specific area where you’ll be walking and for the time you expect to return. If forecasters warn of thunderstorms and there are no accessible buildings or enclosed cars along your route, postpone your walk or choose a short route near safe shelter. This is especially important for a hike: on an exposed trail or high ground, you could end up far from help.

• Mark substantial buildings you can enter and parking areas with enclosed cars along your route.
• Check local thunderstorm alerts before you leave and during your walk; the forecast can change.
• Decide in advance where you’ll turn back if the sky darkens or the wind suddenly picks up.
• If your route crosses hills, a waterfront, or open terrain, plan to turn back earlier.
• Don’t assume an app or phone will warn you about every dangerous lightning strike.

Don’t wait for the first thunderclap if you can already see storm clouds or flashes, or the weather is rapidly worsening: it’s safer to turn back while you can still reach shelter without rushing. And a clear patch of sky above you doesn’t guarantee safety—a lightning strike can come from the direction of the storm, even if it isn’t raining where you are yet.

On your walk: don’t wait for the rain

A thunderstorm is dangerous not only in a downpour, and not only when a cloud is directly overhead. The CDC says lightning can strike beyond the area of heavy rain, and that the risk can be present before a downpour starts or after it seems the storm has passed. So pay attention to thunder, lightning, and official alerts—not just to whether the road is wet.

If thunder catches you in a park, choose a safe destination first, then take the shortest route to it. Don’t linger under trees or continue along an exposed waterfront. If you can’t see shelter, head for the nearest substantial building or enclosed car, avoiding high ground, water, isolated tall objects, and power lines.

Where to wait out a thunderstorm

The safest everyday option is an enclosed, substantial building—for example, a house, shop, school, or station you can go inside. Once inside, stay away from windows and doors, don’t stand on a porch, and avoid touching plumbing, wires, or appliances plugged into an outlet. You can use your phone as long as it isn’t plugged in to charge. The NWS explains separately which objects inside a building can conduct electricity.

If there’s no building nearby, an enclosed car with a metal roof and closed windows can be a suitable alternative. That’s not because rubber tires “insulate” the car: protection comes from its outer metal shell, which carries the electrical current around the outside. Stay inside and don’t lean against metal parts. The NWS explains how this protection works and warns that a lightning strike can damage a car.

Why trees and bus shelters won’t keep you safe

A tree can take a lightning strike, but the electrical current doesn’t necessarily stay in the trunk. It can travel through the branches and trunk, jump to someone nearby, or spread across the ground. So standing under a tree canopy isn’t the same as being in safe shelter. The risk is especially clear with a tall, isolated tree in an open area, but you shouldn’t assume you’re protected in a forest during a thunderstorm either.

A bus shelter with a roof protects you from rain, but a typical open shelter isn’t an enclosed building or vehicle. Its roof and supports can conduct electricity, and its open sides don’t shield you from a strike or current traveling along the ground. The NWS lists open shelters and similar small structures as unsuitable places to shelter; an official safety handout specifically mentions bus stops. If there’s an enclosed station pavilion or a shop nearby, choose one of those instead of a roadside shelter.

In a European study of fatal cases, trees were often mentioned when the report described the shelter people used; they appeared in 157 of the cases where a shelter was mentioned. But this database doesn’t have an appropriate denominator: the researchers didn’t compare everyone who stood under a tree with everyone who was in a building. So this isn’t proof of the exact likelihood of injury—it’s a reminder that people do seek protection from bad weather under trees, even though they aren’t safe shelter from lightning.

If there’s no safe shelter nearby

There’s no completely safe place outdoors. If you can’t reach a building or enclosed car quickly, don’t linger on a summit, ridge, open field, or by the water. Move away from isolated tall objects, metal fences, poles, and wires. Don’t lie on the ground: current from a lightning strike can spread across the surface. These steps only reduce some risks and are not a substitute for shelter.

Don’t waste precious time trying to shelter under a tree, in a tent, or beneath a canopy. If a storm catches you on a trail, keep moving toward suitable shelter and don’t gather your group under a single tree. The NWS guidance for being outdoors stresses that without a safe building or car, your options for reducing risk are limited.

When it’s safe to head out again

Stay in a safe building or car for at least 30 minutes after the last thunder. If you hear thunder again, start the timer over. Use the last sound of thunder as your guide—not when the rain stopped or when you last saw a flash. This is an NWS recommendation to reduce risk; if local authorities advise waiting longer, follow their instructions.

Before continuing, check alerts and the condition of your route: after a storm, there may be flooding, fallen branches, or damaged wires. If the sky darkens again, you hear thunder, or a thunderstorm warning is in effect, don’t head out. You can make up the missed steps another day; going back onto an exposed stretch won’t make you safer.

If someone nearby is injured

Call your local emergency services and follow the dispatcher’s instructions. It’s safe to touch someone who has been struck by lightning: their body doesn’t hold an electrical charge. If conditions allow, move them to a safe place and give first aid within your abilities. But first make sure the storm isn’t putting you or anyone helping at risk.

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