What Is Anvil?
The flat, spreading top of a thunderstorm, shaped like a blacksmith's anvil. It forms when the rising air hits a layer it cannot punch through and spreads sideways. In technical terms: The flat, fibrous, often wind-sheared ice-crystal outflow at the top of a mature cumulonimbus (incus supplementary feature), spreading laterally near the equilibrium level, usually close to the tropopause; can extend hundreds of kilometers downstream.
Also called: Incus
Anvil In Plain English
The flat, spreading top of a thunderstorm, shaped like a blacksmith's anvil. It forms when the rising air hits a layer it cannot punch through and spreads sideways.
The Technical Definition
The flat, fibrous, often wind-sheared ice-crystal outflow at the top of a mature cumulonimbus (incus supplementary feature), spreading laterally near the equilibrium level, usually close to the tropopause; can extend hundreds of kilometers downstream.
