These large masses of slow-moving ice occur where winter snowfall exceeds summer melt
Glacial movement occurs when the growing ice mass becomes too heavy to 
maintain ... As the glacier proceeds to move downslope, the flow lines of the ice 
begin to... [DOC] [TLE] GG101 Glaciers - Honolulu Community College [PAR] Glacial ice originates whenever winter snowfall exceeds the summer melting in a 
given area over ... Only with ice, of course, these changes take place at much 
lower ... We might also note that this moving ice is a very effective erosional agent
.