äikeserinnad

Äikeserinnad refers to a specific type of cloud formation associated with thunderstorms. It is characterized by its anvil-like shape, hence the name, which is derived from the Estonian words "äike" meaning thunderstorm and "rinnad" meaning breasts or humps, collectively suggesting a chest-like or mountainous form. This distinctive shape is a result of the strong updrafts within a cumulonimbus cloud reaching the tropopause, the boundary between the troposphere and the stratosphere.

When the rising air parcel encounters the tropopause, it can no longer ascend vertically. Instead, it spreads out horizontally, forming the characteristic flat, fibrous top of the äikeserinnad. This spreading effect can be amplified by upper-level winds, further extending the anvil shape downwind. The äikeserinnad is a visual indicator of a mature and powerful thunderstorm, suggesting significant atmospheric instability and the potential for heavy precipitation, lightning, and severe weather phenomena. Observing the development and extent of the äikeserinnad can provide clues about the intensity and trajectory of a storm.