Morphostratigraphic relations of glacial moraine complexes at several canyons in the east-central Sierra Nevada show that on several occasions younger glaciers chose paths different from previous glaciers when not confined within the bedrock walls. The tectonic activity within the eastern Sierra Nevada is probably the principal mechanism initiating glacial avulsion. Morphostratigraphic and age relations of moraine complexes determine where and when the avulsion events took place, but do not satisfactorily explain the mechanisms which caused the avulsion. The next ice advance rode on top of the low deposits, raising its base to near the level of the confining lateral moraines. Melt water and small lobes of ice flowed over the lateral moraine for a period of time, but did not fully change the path of the glacier.
Glacial avulsion appears to be polygenic.
The time of avulsion can be determined using surface exposure dating techniques, allowing comparison to other paleoclimatic and paleohydrological data to extract a clearer signal as to the trigger of the avulsion event.