How to survive when lightning strikes in a storm

Lightning is not as common in the UK as is in many other countries, however the consequences of being caught out can be severe and every year people are struck by lightning in the UK, causing severe injury or death. Tragedies like this are rare – but they do happen, and it’s important to know how to protect yourself. We asked Mountain Instructor and BMC member Mike Margeson, vice chairman of Mountain Rescue England and Wales, to share his know-how.

Check the forecast

The first step towards staying safe, of course, is to plan in advance. Even in high summer, you should never hit the hills without having a look at a specialist forecast.

If thunderstorms are on the forecast then consider how this might affect your objectives and where you are going.  Thunderstorms usually form quickly however, there are signs that thunderstorms are developing, tall cumulonimbus clouds are a good indicator of this. There are also some apps that need to be used with a precautionary warning, but can be used to indicate if there is lightning nearby.

“It is a vital part in any mountain day to have obtained a good weather forecast – for a whole number of reasons, not least to guard against the hazards and dangers of lightning storms,” says Mike. “There are a number of specialist weather forecasting services and good services from the Met Office.”

The Mountain Weather Information Service is, of course, another reliable walker’s standby. Look out for warnings of thundery showers, storm force upland winds and torrential rain – and be prepared to change your plans if necessary.

Keep an eye on the clouds

Local weather forecasts, while generally accurate, can’t always predict when lightning is going to strike. Alongside checking the forecast, it’s important to keep an eye on what the weather is doing while you’re on the hill.

“It is difficult for forecasters to be 100% accurate over timings and storms can be very hard to predict in terms of severity and exact location,” Mike warns. “That’s why being weather wise and observant while you were out is vital.

He advises considering humidity and warmth, as well as what the clouds are doing. “When clouds are seen to becoming towering cumulonimbus and quite obviously menacing, it is a warming indicator and time to review your location and plans. During a period of hot weather, it is wise to consider starting early as the danger will increase during the day as the heat builds up. Your plan for the day should take this into consideration.”

Lose height fast

If you do get caught in a storm then the general advice is to descend as quickly as is safely possible. The higher and more exposed you are, the greater the danger. It may seem counter intuitive, but don’t seek shelter under cliffs, caves, mine entrances or trees – all of which could put you at greater risk if they are struck by lightning. Instead, aim to ensure that there is higher ground above you.

“It is recommended that you find the lowest open ground space and sit on your rucksack,” says Mike. He advises separating yourself from metal kit, such as tent poles, ice axes or climbing hardware, and avoiding metal fence lines.

Of course, you might find yourself stranded partway up a climb. In that case, it might be wisest to stay put. “If you are actually scrambling or on a climb it is a difficult situation, but the advice is not to start abseiling as a wet rope might act as a conductor to dissipate a lightning strike,” explains Mike.

If you do get caught out in a thunderstorm, what should you do?

Warnings of an imminent lightning strike can include your skin tingling or hair standing on end. If you experience either of these symptoms then crouch down on the balls of your feet to minimise contact with the ground, but don’t lie down. It’s a myth that you can put yourself in danger by assisting somebody who has been struck by lightning as no electric charge remains after the event. Attempt CPR on a companion with no pulse or breath and seek help straight away, even if they seem to be fine.

Measure how far away the thunderstorm is

Your distance from a thunderstorm can be estimated by measuring the time between seeing the lightning flash and hearing the thunder. The length of this interval in seconds can be divided by three to give an approximate distance in kilometres.  E.g. 6 seconds between the lightning and thunder would suggest the storm is 2km from you.  Monitor this timing to assess if the storm is approaching you or heading away. The calculation above is a useful guideline BUT it is important to realise that if you hear thunder, you are already within range of where the next strike may occur – lightning can strike as far as 14km away from the storm. In addition, on windy days the sound may be muffled, or you may not be able to hear the thunder over the wind noise, so be vigilant for any lightning flashes.

Remain cautious after the storm

The threat of lightning continues for much longer than many people realise. After the storms move away and you stop hearing thunder wait at least 30 minutes before assuming it is safe.

Get down when you hear thunder

If you hear thunder it is vital to get down off high ground immediately.  Lightning will take the shortest route to earth, so if you are the highest point in the immediate vicinity drop down off the summit, exposed ridge line etc if it is safe to do so.

Minimise chances of being hit by becoming small

Regardless of where you are outside, even on lower ground, there is no safe place from lightning.  To minimise the chances of a strike you need to become a small, round target. Your best option is to put extra clothing and waterproofs on, seek the lowest point possible and sit on your rucksack with your knees drawn up to your body. Or squat close to the ground, with hands on knees and with head tucked between them. Try to touch as little of the ground with your body as possible; do not lie down on the ground. If you feel your hair stand on end, drop to the above position immediately.

Place metal gear far away from you

Make sure that you place any items such as poles, ice axes, crampons and climbing hardware well away from you until the storm has passed. If any of your equipment is ‘buzzing,’ move away from it immediately. Another feature is the emission of a blue glow to the buzzing equipment. This is a phenomenon known as St. Elmo’s fire and can indicate that a strike is likely to be imminent.

Don't shelter in a cave

Sheltering under a rock overhang or in a cave is hazardous because a lightning strike will bridge the gap between the rock above you and the ground below.

Avoid trees and water

Trees are uncommon above 600 metres in the mountains, however the same message of staying away from any tall objects. Do not position yourself next to a brook, near water or boggy ground or anywhere that can conduct electricity more.

Keep your distance from each other

Move away from each other if you are in a group; then if the worst occurs it is likely that there will be others to help. “If you come across somebody or somebody in your party is struck by lightning and seems to be alright you should still seek Mountain Rescue assistance urgently,” says Mike. “Anybody that has been affected by electrical charge should still be medically checked and potentially considered at risk, as the heart relies on the correct electrical rhythm and there could be post incident complications.

Don’t panic!

While lightning strikes on high summits and ridges are fairly common, fatalities in the UK are actually rare. Don’t let sultry weather keep you out of the hills – just remember that planning and mountain awareness are the most important defences against trouble.

Go on a course

• Hill and Mountain Skills: The BMC's partner organisation Mountain Training has just launched its new Hill and Mountain Skills Courses. They aim to equip you with the basic knowledge and safety skills required to participate in hill and mountain walking in your own time and are run by providers all over the UK.

Get covered with BMC Travel Insurance

BMC Travel Insurance is designed by climbers and mountaineers, for climbing, walking and mountaineering.

• Take out BMC Travel & Activity Insurance online or call our team of experts on 0161 445 6111.

• 24-hour emergency assistance is just a phone call away. Specialty Assist (+44 20 7902 7405) is the first port of call in an emergency. The number will be on your BMC Travel Insurance policy card.