Category: Lightning

Thunder is produced mainly within cumulonimbus clouds. Cumulonimbus clouds contain very small ice particles and relatively large hail. When they collide, the small ice particles are electrified positive ions and the hailstones are electrified negative ions.

The lighter small ice particles with positive charges gather above the cloud, and the heavier hail with negative charges gather below the cloud, so the negative charges at the bottom of the cumulonimbus cloud attract and the positive charges accumulate on the ground below.

Between the clouds and the ground when a certain amount of electricity accumulates, light and sound discharges are produced, thunder is heard and lightning is seen.

1. The voltage of lightning is said to be about 200 million volts. Air does not normally conduct electricity, but in the case of lightning, the voltage is so high that it can conduct electricity through the air and discharge.

2. In fact, lightning can occur even in the absence of cumulonimbus clouds. One of these phenomena is called “volcanic thunder”. Volcanic thunder occurs when a volcano erupts.

According to the Meteorological Agency, on the Japan Sea side, thunder occurs all year round, and there are many places where thunder occurs even in winter. There are fewer thunderstorms, though in winter, and there is a part of the Atlantic coast which also has thunderstorms in winter. Thunder in winter is slightly different from thunder in summer. Winter thunder is very powerful and has fewer discharges, so winter thunder is also known as a single one, and its energy is about 100 times that of summer thunder. Summer thunder can be heard from a distance, so it is easy to take precautions, but winter lightning has very few discharges, which means it can approach silently and then strike suddenly.

3. In addition to the damage to the human body from being struck lightning, there are malfunctions in electrical appliances such as computers and televisions due to high currents flowing through them, as well as fires in forests and buildings.

1. If you hear thunder, seek shelter quickly in a nearreinforced concrete building or in a car. The best place to take shelter is in a reinforced concrete building, in the middle of a room or in a car.

2. Unplug appliances and turn off circuit breakers. Even indoors, proximity to poles and appliances can be dangerous. Lightning currents can also flow through wires and cables such as TV and telephone lines, so it is important to stay away from household appliances and avoid touching them. It is necessary to install protective equipment inside the building.

3. Do not take shelter from the rain on or under tall trees. When lightning strikes a tree, it will also pass through people close to the trunk. To avoid being struck lightning from a tree, keep at least two meters away from the tree branches.

4. Do not take shelter from the rain under the eaves. If lightning strikes the house where you are sheltering from the rain, a large current will flow through the eaves. It is more likely to pass through wetter bodies than through walls and columns that are less permeable to electricity, so the lightning current is likely to be carried partially on the side strike. The best place to take shelter from the rain is inside a building, not under the eaves.

5. If there is no place to take shelter nearby, keep as low a posture as possible.

6. Check the weather forecast and lightning forecast before leaving home.