Sentence:  While accounts of the progress of the tsunami came in from various points in the Pacific ( Midway reported it was covered with nine feet of water ) , the Hawaiian station made its calculations and notified the military services and the police that the first big <WSD>wave</WSD> would arrive at Honolulu at 23 : 30 Greenwich time . 
Meaning of the word marked with <WSD> tags:  one of a series of ridges that moves across the surface of a liquid (especially across a large body of water)