Antarctic Dictionary
growler
growler noun
[Growler is used in both Polar regions; the earliest example so far noted in arctic use is also 1912.]
A piece of iceberg or other ice, almost submerged beneath the sea's surface and hence dangerous to ships; occasionally one frozen into the sea surface. These pieces are almost always regarded as smaller than bergy bits but the main distinction is their lack of prominence above the water.
The Antarctic Dictionary, Hince, 2000; 161