Glaciers Flashcards
Ice sheets
A large mass of glacial land ice that covers more than 50000km2
Ice caps
Large mass of glacial land ice that covers less than 50000km2, usually found in mountainous areas
Valley glaciers
A slow-moving river of glacial ice which is confined within valley walls
Corrie glaciers
A small glacier that develops high up on a sheltered mountainside
Snow patches
Small area of snow and ice which are usually found on north facing mountain slopes
Where does snow fall regularly
In cold areas
What happens if the temperatures are cold enough
The snow doesn’t melt
How is fresh snowfall (%)
About 10% ice crystals and 90% air
How are glaciers formed
As more snow falls every year, the weight of layer after layer of snow compresses the lower layers.
As more snow is compressed, much of the air is removed and the snow becomes harder and more dense.
After 1 year, the fresh snow becomes harder and more granulated snow which is about 40% ice crystals and 60% air. This layer is called FIRN
Over the years, the lower layers are compressed even further to become GLACIAL ICE which is about 90% ice crystals and 10% air.
How can the glacier be in a state of balance
Glaciers are a system of inputs (new snowfall) and outputs (meltwater and evaporation). If the rate of accumulation (new snowfall) is equal to the rate of ablation
When will the glacier grow and advance downhill under its own weight
If the rate of accumulation exceeds the rate of ablation
When will the glacier shrink and retreat up slope
If the rate of ablation exceeds the rate of ablation
What is a glacier
A large body of snow and ice which moves downhill under its own weight
