noun
- granular snow that becomes compacted and dense but has not yet turned into glacial ice
Usage: technical term used in glaciology and mountaineering
Examples
- The climbers trudged through deep firn on their way up the mountain.
- Firn accumulates in the upper regions of glaciers where snow persists year after year.
- The transition from firn to solid ice takes many decades.
- Alpine skiers must be careful when crossing fields of firn, as it can be unstable.
- Glaciologists study firn layers to understand past climate patterns.