The big breakers came in slowly; their shoulders growing tall and green. They crashed in thunderous white, and we would sit in silence, the breezes scrubbing the hot sun from our faces. (Source)
In this paragraph, what does the phrase "crashed in thunderous white" mean? Moreover explain its composition to me from grammatical point of view.
This is an evocative phrase meant to convey a particular image rather than information. It's not meant to be taken literally, but rather to express the power of the waves and the amount of white spray thrown into the air when the waves break.
Similar examples:
The massed red uniforms of the enemy made a sea of shouting crimson.
The pristine lake was an azure jewel set in the middle of the green mountains.
