Under what conditions will the firn limit remain the same from ...

[appyboo]

Under what conditions will the firn limit remain the same from year to year? Under what conditions
  will it change? What happens if the firn limit moves upward year after year? What will be an ideal response?

Question 2

What are the zone of accumulation, zone of wastage, and firn limit? What will be an ideal response?

[duke02]

Answer to Question 1

The firn limit will remain the same if accumulation equals wastage. The firn limit will move up the
glacier if more snow is lost than accumulated in a year, and will move down the glacier if more snow
is accumulated than lost in a year. Eventually, a negative budget will result in a glacier becoming too
thin to maintain flow. It will be a stagnant glacier and eventually disappear.

Answer to Question 2

The upper part of a glacier is the zone of accumulation, where the addition of snow exceeds losses and
the surface is perennially snow covered. The lower part of a glacier is the zone of wastage where snow
is lost from melting, sublimation, and calving of icebergs in excess of the amount that zone
accumulates. Snow accumulates in winter but melts in spring and summer. The elevation to which
snow recedes during the wastage season is the firn limit.