Explain why lightning often strikes the highest points.

Principle of formation and path of lightning

During a storm, the cloud becomes electrically charged due to intense movements of air and water or ice inside. This creates a separation of charges with negative areas at the bottom and positive areas at the top. As a result, a huge electric field forms between the cloud and the ground, ready to strike. When the voltage becomes enormous, a descending streamer, a kind of conductive path, travels from the cloud to the ground. In the opposite direction, from the ground, other small streamers attempt to connect with the one coming from above. As soon as contact is made, bam, a conductive channel is established and the bright flash appears with a violent electric exchange, often followed by a loud clap of thunder. This lightning path generally takes the easiest and shortest route to the ground: often something high, pointed, or conductive.

The importance of elevated areas in lightning strikes.

Lightning does not choose its path randomly; it naturally seeks the easiest way to connect the electrically charged cloud to the ground. The result? It is often the highest points that attract it first. Why? Simply because elevated areas, such as treetops, antennas, or buildings, minimize the distance between the sky and the ground. Less distance to travel means less resistance, making it the royal road for electricity. These high places also create an accumulation of electric charges at their tips, a phenomenon known as the tip effect, which further encourages the arrival of lightning. That’s why lightning is more often attracted to church steeples or mountain peaks rather than the peaceful meadow right next door.

Electrical conductivity and peak effect

Lightning does not follow just any path; it primarily chooses objects with good electrical conductivity. The easier a material conducts electricity (like metals), the more it attracts lightning. This is where a particular phenomenon called point effect comes into play. When an object has a thin and pointed shape—like an antenna or a steeple—electric charges accumulate more at its tip. As a result, the surrounding air ionizes more quickly, facilitating the formation of a lightning strike precisely at that location. This is why lightning rods always have a pointed tip: they naturally concentrate electric charges and effectively protect buildings.

Influence of height and materials on lightning

The higher it is, the more attractive it is for lightning. It's simple: lightning chooses the shortest path to the ground, and tall structures make this choice easier. The Eiffel Tower, for example, gets struck about 5 times a year precisely because it has two advantages: it is very tall and mostly made of metal, an ultra-conductive material. In contrast, you will rarely see a lightning bolt hit a low tree or an object placed close to the ground (unless it has no other choice). Moreover, the material plays a significant role: substances like dry wood or plastic do not conduct electricity very well, so there is less chance that lightning will honor them. But be careful: a wet tree can very well receive a discharge, as water greatly enhances its conductivity.

Concrete cases illustrating lightning striking high points

Every year, lightning regularly strikes famous high points, such as the Eiffel Tower, which is hit several times a year without anyone being particularly surprised. The same goes for the Empire State Building in New York, struck about 25 times each year. Mountain peaks also often attract lightning, like Mont Blanc or Pic du Midi in the Pyrenees, which are very exposed during storms. The same applies to isolated trees, especially those perched on top of a hill, where lightning often prefers to strike directly at their tip. These concrete examples clearly prove one thing: the higher and more isolated it is, the more comfortable lightning feels there.