Presently the white flood comes bounding into sight over bosses and sheer places, leaping from bench to bench, spreading and narrowing and throwing off clouds of whirling dust like the spray of foaming cataracts.

Compared with waterfalls and cascades, avalanches are short-lived, few of them lasting more than a minute or two, and the sharp, clashing sounds so common in falling water are mostly wanting; but in their low massy thundertones and purple-tinged whiteness, and in their dress, gait, gestures and general behavior, they are much alike.
Avalanches Besides these common after-storm avalanches that are to be found not only in the Yosemite but in all the deep, sheer-walled canyon of the Range there are two other important kinds, which may be called annual and century avalanches, which still further enrich the scenery.

The only place about the Valley where one may be sure to see the annual kind is on the north slope of Clouds' Rest.

They are composed of heavy, compacted snow, which has been subjected to frequent alternations of freezing and thawing.

They are developed on canyon and mountain-sides at an elevation of from nine to ten thousand feet, where the slopes are inclined at an angle too low to shed off the dry winter snow, and which accumulates until the spring thaws sap their foundations and make them slippery; then away in grand style go the ponderous icy masses without any fine snow-dust.