How is weather lighting created? – SWR knowledge

When the atmosphere flickers

Lightning – that’s what it’s called when the atmosphere flickers. It is vaguely reminiscent of a thunderstorm, except that there is usually no clearly defined lightning and you often don’t hear any thunder.

When the storm is far away

There are two ways in which this phenomenon occurs: lightning is either a thunderstorm that is so far away that you cannot see the lightning itself – for example because it is behind the horizon. You then only see the layers of air that are illuminated by the lightning. The light from the lightning can be reflected on one or two clouds as it travels through the atmosphere, giving the impression of diffuse flickering – in contrast to the sharp flash of a thunderstorm in the immediate vicinity.

Lightning discharges within a cloud

The second possibility: In addition to the normal lightning bolts that we know from thunderstorms – the lightning bolts that strike from a cloud to the ground – there is also lightning within clouds. A thundercloud is negatively charged at the bottom and positively charged at the top, so lightning discharges can occur from bottom to top even within a cloud. But because these lightning bolts are surrounded by the cloud itself – i.e. by water droplets and ice crystals – the light in the clouds is scattered so that from a distance it looks more like flickering.

Faint humming or no thunder at all

Basically, lightning is always followed by thunder – simply because the lightning heats the air so much that it “releases” a sound wave. However, when there is lightning, the thunderstorm is so far away that you either don’t hear the thunder at all, or you only hear a faint hum – which then perhaps comes with such a delay that you no longer associate it with lightning. The further away a thunderstorm is, the longer the sound takes and the more time passes between lightning and thunder.