Bristol has seen its fair share of storms this week as temperatures hit a sweltering 30 degrees and above.
But although the skies have been lit up by lightning, many people have reported hearing little to no thunder – and are wondering why.
Lightning comes in the form of a giant electric spark in the atmosphere, or between the atmosphere and the ground.
In its early development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground.
However, when the differences in charges become too much, the capacity of the air breaks down and a rapid release of electricity is discharged, forming lightning.
According to the Met Office, when lightning is seen without hearing thunder, it normally means you are not close enough to the storm, as it is impossible for lightning to strike without thunder.
It is likely you were further than 12 miles (20km) from the lightning strike, as atmospheric conditions also affect whether thunder can be heard or not, as the sound can be pushed up and away from the surface.
Also, a flash of lightning, however, can be seen from up to 100 miles away.
The distance from a thunderstorm can be estimated by measuring the time between seeing the lightning flash and the hearing the start of thunder.
The length of this interval in seconds can be divided by three to give an approximate distance in kilometres.
A Met Office spokesman said: “Sometimes lightning may be seen but there is no thunder heard.
“This is either because thunder is rarely heard more than 20 km away or because the atmospheric conditions lead to sound bending upwards and away from the surface.”
For those who heard occasional thunder, it is likely they could ony hear the biggest rumbles in the storm.
Non-stop lightning goes by a number of different names, including silent lightning, summer lightning, dry lightning and heat lightning.
It is most often called heat lightning as the phenomenon regularly occurs during the summer months.
Here are the main types of lightning you may see during the storms this week.
- Ball lightning – a rare form of lightning in which a persistent and moving luminous white or coloured sphere is seen.
- Rocket lightning – a very rare and unexplained form of lightning in which the speed of propagation of the lightning stroke is slow enough to be perceptible to the eye.
- Pearl-necklace lightning – a rare form of lightning, also termed ‘chain lightning’ or ‘beaded lightning’, in which variations of brightness along the discharge path give rise to a momentary appearance similar to pearls on a string.
- Ribbon lightning – ordinary cloud-to-ground lightning that appears to be spread horizontally into a ribbon of parallel luminous streaks when a very strong wind is blowing at right angles to the observer’s line of sight.
- Forked lightning – lightning in which many luminous branches from the main discharge channel are visible.
- Sheet lightning – the popular name applied to a ‘cloud discharge’ form of lightning in which the emitted light appears diffuse and there is an apparent absence of a main channel because of the obscuring effect of the cloud.
- Streak lightning – a lightning discharge which has a distinct main channel, often tortuous and branching, the discharge may be from cloud to ground or from cloud to air.