Then there is a grand crashing of breaking ice and dashing of waves mingled with the low, deep booming of the avalanche.
Detached masses of the invading snow, mixed with fragments of ice, drift about in sludgy, island-like heaps, while the main body of it forms a talus with its base wholly or in part resting on the bottom of the basin, as controlled by its depth and the size of the avalanche.

The next avalanche, of course, encroaches still farther, and so on with each in succession until the entire basin may be filled and its water sponged up or displaced.

This huge mass of sludge, more or less mixed with sand, stones, and perhaps timber, is frozen to a considerable depth, and much sun-heat is required to thaw it.

Some of these unfortunate lakelets are not clear of ice and snow until near the end of summer.

Others are never quite free, opening only on the side opposite the entrance of the avalanches.