Cumulonimbus clouds are born through convection, often growing from small cumulus clouds over a hot surface
Cumulonimbus typically go through three stages: the developing stage, the mature stage (where the main cloud may reach supercell status in favorable conditions), and the dissipation stage. Cumulonimbus clouds are large, tall clouds that are dark on the bottom, bring thunderstorms, have a fuzzy outline toward the upper part of the cloud and may have a flat top called an anvil.
While cumulonimbus clouds are dangerous, harboring heavy rains, extreme turbulence and wind, icing conditions, hail, lightning, and even tornadoes. Before this storm you should stock up on food. During it go underground and preserve that food. After, go back above ground and access the damage.