Cumulonimbus clouds are menacing looking multi-level clouds, extending high into the sky in towers or plumes. More commonly known as thunderclouds, cumulonimbus is the only cloud type that can produce hail, thunder and lightning.

Why are cumulonimbus clouds so powerful?

Cumulonimbus (from Latin cumulus, "heaped" and nimbus, "rainstorm") is a dense, towering vertical cloud, forming from water vapor carried by powerful upward air currents. ... These clouds are capable of producing lightning and other dangerous severe weather, such as tornadoes and hailstones.

What are the characteristics of a cumulonimbus cloud?

Cumulonimbus clouds are one of the most recognisable cloud types, characterised by their threatening anvil-shaped tops and the torrential rain, hail, thunder and lightning that they often produce. They are the tallest clouds we see, and can extend through the entire height of the troposphere.