åsksvågor

Åsksvågor, meaning "thunder waves" in Swedish, is a colloquial term used in meteorology, particularly in Scandinavian countries, to describe the phenomenon of thunder occurring without visible lightning. This can happen for a few reasons. One common cause is that the lightning strike occurs very far away, beyond the distance where the flash is visible. The sound waves, however, travel further and can still be heard. Another possibility is that the lightning is obscured by cloud cover, rain, or terrain, preventing the visual flash from reaching the observer. In some cases, the lightning might occur entirely within a cloud (cloud-to-cloud) or within a thunderstorm cell at a distance, making it invisible from the ground. Despite the lack of a visible flash, the thunderclap is still produced by the rapid expansion of air heated by the electrical discharge, and these sound waves propagate through the atmosphere. Therefore, åsksvågor refers to the auditory experience of thunder without the accompanying visual spectacle of lightning. It does not represent a distinct meteorological event but rather a perceptual difference in observing a thunderstorm.