| Answer | Crossword Clue |
|---|---|
| cumulus | A cloud forming rounded masses heaped on each other above a flat base at fairly low altitude |
| cumulonimbi | A cloud forming a towering mass with a flat base at fairly low altitude and often a flat top, as in thunderstorms |
| cumulonimbus | A cloud forming a towering mass with a flat base at fairly low altitude and often a flat top, as in thunderstorms |
