Glaciers will only form under certain conditions and in specific environments. A cold climate and sufficient moisture in the air for the precipitation of snow are both necessary factors that permit at least some snow to last year-round. This allows for the build-up and compaction of snow that will eventually become glacial ice. Sufficiently cold climate conditions exist at high altitudes and high latitudes.
Explanation:
There must be landmasses at high latitudes for continental glaciers to occur, as they cannot form over open water. While persistent sea ice can and does form, because it floats, it does not flow as a glacier does.
