What are cumulonimbus and alto stratus clouds?

Cumulonimbus clouds are large, towering clouds associated with thunderstorms and severe weather, characterized by their vertical development and anvil-shaped tops. They can produce heavy rain, lightning, hail, and tornadoes. In contrast, altostratus clouds are mid-level, gray or blue-gray clouds that typically cover the sky and often precede storms with continuous rain. They are generally more uniform in appearance and do not have the vertical development seen in cumulonimbus clouds.