Could be an iceberg, or an ice flow.
The verb form can be an adjective (e.g. drifting ice, drifting debris).
Icebergs (drifting ice) in Antarctica have broken off from the glaciers and ice shelves that stretch out over the sea at the continent's coastline.
Floe
Drifting sea-ice from ~860 A.D.
"leads"
The icebergs had been drifting further South than usual.
because of all the ice drifting to town you would not feel it and because we don't have lot's of ice anyway
drifting
The Norwegian explorer, Fridtjof Nansen proved the Arctic was a deep polar ocean with a drifting ice cap in the late 1890's. Previously there were ideas that within the belt of ice, open shallow water, perhaps land surrounded the North Pole.
all the continents are drifting
No, the word "drifting" is not an adverb.The word "drifting" is a noun and a verb.The adverb form of the word is driftingly.
Not a glacier, but an iceberg, which was drifting South from the Arctic regions after breaking off from the Polar ice-cap in the warmer Spring weather.