Thunderstorms: how you can protect yourself

A number of factors have to come together simul­taneously for a thunder­storm to develop: certain wind and air pressure conditions and a correspon­ding terrain. This causes warm and humid air in higher strata to become not a normal cloud, but a thunder­cloud. It is huge and can hold up to 100 million tons of water.

There are strong updrafts in the thunder­cloud, hurling the water droplets even further upwards, where they freeze into ice crystals that rub against each other. This is one of the reasons why an electrical charge builds up and finally discharges as lightning. This occurs especially in summer when it is hot and a lot of water evaporates. Including secondary lightning, lightning strikes around 150,000 times in Switzerland, according to MeteoSwiss, with southern Ticino being the unrivaled lightning hotspot.

In the Swiss Plateau, the weather services can usually announce thunder­storms a few hours in advance. But in the mountains they sometimes strike literally “out of the blue.” It is therefore all the more important to know the most important rules of conduct.

• Every year, several people are struck by lightning in Switzerland. Most survive – but sometimes a lightning strike can be fatal. You should therefore reduce the risk of being struck as much as is possible.
• Take thunderstorm warnings seriously and find out about current weather developments, for example with the push app from MeteoSwiss.

• The old adage states that you should "avoid oaks and seek out beeches," but sadly this isn’t a good idea. Avoid exposed trees, groups of trees, high bridges, masts, or towers, because lightning is particularly prone to strike where something protrudes out of the landscape.
• Metal and water also attract lightning. Leave the water immediately when swimming or sailing. Park your bike or motorbike if you are traveling with it.
• If you get caught in a thunderstorm while hiking, run to a hollow and squat down in a crouched position. Please note that the metal anchors of secured paths or climbing trails can also attract lightning.

• Seek shelter in your car: It forms a "Faraday cage" so that a lightning strike cannot reach you, since the metal deflects the lightning outside. You are also safe in buildings equipped with lightning conductors.
• And finally: Before leaving your home, unplug electrical appliances such as televisions and computers, otherwise there is a risk of damage due to overvoltage and possibly fire.