Thunderhead

Half the sky was checkered with black thunderheads, but all the west was luminous and clear:

The wisps of smoke above Léogane became dark and thick, and flowered into a towering thunderhead—an ominous cloud that drifted slowly to the westward and was constantly replenished at its base by uprushes of blacker smoke.

The sky ahead was huge with storm: all the whiteness had gone from the thunderheads, and they rolled and swirled with sulphur yellow, sea green, smoke gray, oil black, a queasy churning miles high and as wide as the horizon.