The huge waves rose black as thunder-clouds, hurled their white froth toward heaven, and sank with sullen roar back into the deep.
"These are thunder-clouds driving under us," replied her mother.
It was swept by the close-range fire of the Germans, like rain from thunder-clouds.
So he sent them above, where they became the thunder-clouds.
She seemed molded from fire and air, and vivified at some Voltaic pile of August thunder-clouds heaped against the sunset.
Her blue eyes were dark as thunder-clouds in their earnestness.
The sea in the offing was black and rolling; thunder-clouds lay low on the horizon, split by broad flashes of lightning.
The height of these thunder-clouds has been much under-estimated.
A hot July, winged with thunder-clouds, brooded over the meadows by the Whit.
It had piled the thunder-clouds high and higher, and now and again a heavy drop of rain tapped at her window like a thrown pebble.
Plural cumulonimbi (kym'yə-lō-nĭm'bī)
An extremely dense, vertically developed cloud with a low, dark base and fluffy masses that tower to great heights. Cumulonimbus clouds usually produce heavy rains, thunderstorms, or hailstorms. Also called thundercloud. See illustration at cloud.