[rmu09]

Ice growth on a glacier is what remains of snow over one year. I don't know proper english jargon, but glaciers usually accumulate snow from around october to june. June to october is the melting period.

Obvious: glacier growing means it accumulates more snow (that will slowly convert into solid ice) than is melting in the summer.

[saiya-jin]

Exactly, there is no magic - all the ice is just snowfall compressed over time, by its own weight and melting/refreeze cycles.

This autumn has been really great for outdoors but disastrous to glaciers - extremely warm till end of october, no precipitation at all for more than a month.