First there is a soft rumble in the distance. Then the first lightning flashes in the sky and the storm breaks out. Thunderstorms are not uncommon, especially in summer. Many are afraid of the weather phenomenon, because thunderstorms can be deadly. In Germany there are between 20 and 35 days of thunderstorms every year. The force of nature cannot be tamed by humans. The voltage between cloud and earth is up to 100 million volts before discharge.
The current can be tens of thousands of amperes, and lightning can reach temperatures of up to 30,000 degrees. If lightning strikes damp masonry or a tree, the water contained therein evaporates explosively. Even thick oaks are split by it. For people, a lightning strike often has serious health consequences, including death.
More extreme weather conditions due to climate change
Thunderstorms and extreme weather have increased significantly in recent years. For meteorologists, these unusual phenomena are already the first consequences of climate change: The fact that the greenhouse effect is melting the polar caps is leading to extreme changes in air currents, especially in Germany. Since high and low pressure areas stay in one place for longer, there are more thunderstorms with dangerous lightning strikes.
Warm air meets cold air: This is how a thunderstorm develops
A thundercloud forms when hot and cold air masses meet. Water and ice particles form in the cloud and become electrically charged. A voltage field builds up that amounts to several hundred million volts. Eventually there is a gigantic short circuit and lightning lights up the sky.
How can the thunder after lightning be explained?
When lightning strikes, current flows with a strength of up to 400,000 amperes. This heats up the air enormously. It expands explosively and creates an acoustic shock wave: thunder.
Can the distance of a thunderstorm be measured?
Yes, you count the seconds between lightning and thunder and divide that number by three. The result indicates approximately how many kilometers away the thunderstorm is. Experts advise: seek shelter if there is less than six seconds between lightning and thunder.
Correct behavior: what protects against thunderstorms?
When severe weather warnings are issued, people should seek protection from thunderstorms in good time and be sure to observe these rules of conduct:
- Before hiking – especially in the summer months in the mountains – take a look at a weather app. If thunderstorms are forecast, it is better to postpone the tour. The risk of thunderstorms is generally lowest from early morning to midday. It is also advisable to find out in advance about the locations of lightning-proof shelters.
- If you are surprised by a thunderstorm in an open area, you should look for a hollow in which you can crouch. There, on an insulating surface – such as an empty backpack or a sleeping pad – squat down and clasp your legs with your arms. Don’t lie down, otherwise the body offers too large a target for lightning.
- In forests, you should go to a clearing or the edge of the forest, crouch there and make yourself as small as possible.
- Trees do not offer protection from thunderstorms, on the contrary. Lightning discharges look for high points. This includes antennas, towers, masts or tall trees. The well-known saying “You should look for beeches, you should give way to oaks” is simply wrong.
- If groups are surprised by a thunderstorm, they should split up, because this also reduces the attack surface in the event of a possible lightning strike.
- Umbrellas, trekking poles, tent poles, bicycles and other metal parts offer a good target for lightning and should be removed from close proximity to the body.
- If you are in or on the water when a thunderstorm is approaching, you should leave it as soon as possible. Swimming in a thunderstorm is life-threatening because lightning can also strike the water.
- Car or train offer the best protection. The principle of the “Faraday cage” works here. The energy is conducted into the earth through the metal shell of the vehicles and is therefore not dangerous for the people inside.
- People are also well protected in residential buildings. However, electrical devices should be unplugged from the socket. Otherwise, lightning strikes in the power supply can destroy the devices due to overvoltage.
First aid in case of lightning: Immediate cardiac massage
If a person is struck directly or indirectly by a lightning strike, the heart often stops. However, there are above-average chances of resuscitation with immediate first aid. More than 80 percent of those affected can be successfully resuscitated within the first five minutes. Therefore, cardiac massage should be started immediately on a lifeless lightning strike victim. Fear of “residual power” is unfounded, it doesn’t exist.