firn
Glacier ice precursor
Firn is granular snow that has survived at least one summer's melt but hasn't yet compressed into solid glacier ice.
It represents an intermediate stage in glacier formation, denser than fresh snow but still porous enough to contain air pockets.
The climbers crossed fields of firn on their approach to the summit.
The term comes from German and is used primarily in glaciology and mountaineering contexts.
Slow-moving ice mass
- snowfieldPermanent snow accumulation area
- icefieldExtensive glacial coverage
- summitPeak or diplomatic gathering
- high-altitudeElevated atmospheric position
mountaineering · expedition · crevasse · ice-axe · crampon · altitude · massif · cordillera
Heat-pressure mineral alteration
- compactionReducing volume through pressure
- sinteringPowder consolidation by heating
- crystallizationForming ordered solid structure
- densificationIncreasing mass per volume
consolidation · recrystallization · granular · porosity · permeability · grain · bonding · microstructure
Collected mass over time
- ablationRemoval by cutting, melting
- crevasseDeep glacial fissure
- seracGlacial ice pinnacle
- percolationLiquid passing through pores
sintering · cryosphere · sublimation · penitentes · superimposed · isotherm · glaciologist · snowfield
glacier
Slow-moving ice mass
- snowfieldPermanent snow accumulation area
- icefieldExtensive glacial coverage
- summitPeak or diplomatic gathering
high-altitude · mountaineering · expedition · crevasse · ice-axe · crampon · altitude · massif · cordillera · snowpack
metamorphism
Heat-pressure mineral alteration
- compactionReducing volume through pressure
- sinteringPowder consolidation by heating
- crystallizationForming ordered solid structure
densification · consolidation · recrystallization · granular · porosity · permeability · grain · bonding · microstructure · cohesion
accumulation
Collected mass over time
percolation · sintering · cryosphere · sublimation · penitentes · superimposed · isotherm · glaciologist · snowfield · densification
firnfresh powder
Newly fallen, uncompacted snow
fresh snow · powder snow · glacial ice · névé · blue ice