Sentence:  Foster had been left unsighted by Scott Dann's positioning at his post, but the goalkeeper was about to prove his worth to Birmingham by keeping them in the game with a series of stunning saves as West Ham produced <WSD>waves</WSD> after <WSD>wave</WSD> of attack in their bid to find a crucial second goal. 
Meaning of the word marked with <WSD> tags:  A sudden unusually large amount of something that is temporarily experienced.