GEO 110 Lecture 4: Class-4-Lecture-Notes
5 Aug 2016
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Firn is partially-compacted snow that has been left over from past seasons and has been recrystallized into a substance denser than n v . It is ice that is at an intermediate stage between snow and glacial ice. Firn has the appearance of wet sugar, but has a hardness that makes it extremely resistant to shovelling. It generally has a density greater than 550 kg/m and is often found underneath the snow that accumulates at the head of a glacier. The ice is compacted and impermeable to air and water and the ice crystals are able to reflect all colours except blue and this gives the. Surges may also be caused by the supply of meltwater to the base of a glacier. Meltwater is important in reducing frictional restrictions to glacial ice flow. The distribution and pressure of water at the bed modulates the glaciers velocity and therefore mass balance.
