Then again from out of the west sounded the low, dull, and rumbling roll of thunder.
A wave, a ripple of light, a trembling and turning of the aspen leaves, like the approach of a breeze on the water, crossed the valley from the west; and the lull and the deadly stillness and the sultry air passed away on a cool wind.
The night bird of the canyon, with clear and melancholy notes announced the twilight.

And from all along the cliffs rose the faint murmur and moan and mourn of the wind singing in the caves.

The bank of clouds now swept hugely out of the western sky.

Its front was purple and black, with gray between, a bulging, mushrooming, vast thing instinct with storm.

It had a dark, angry, threatening aspect.