Linked from
The 6 pages that link to Ablation zone, each with the reason it gives.
GlacierBroader topic: Ice reaching this zone is lost faster than new snow replaces it.
Glacier mass balanceBroader topic: Melting, sublimation, and calving remove mass here.
FirnCompared with: Unlike firn-rich accumulation areas, ablation zones lose mass overall.
Columbia IcefieldRelated: Lower outlet glaciers lose ice as they descend from the icefield.
Tasman GlacierBroader topic: The lower glacier loses ice through melt and calving near Tasman Lake.
Jostedal GlacierRelated: Its outlet glaciers lose ice as they descend into warmer elevations.