Sentence:  An ice <WSD>gorge</WSD> had formed in the bed of the river at the head of the island and from bank to bank logs, driftwood, broken ice and giant floes were packed and jammed so tightly as to resist the action of the mighty current. 
Meaning of the word marked with <WSD> tags:  A choking or filling of a channel or passage by an obstruction; the obstruction itself.