Answer:
The adverb clause is "when the Tigers won the state championship", the subordinating conjunction is "when", and the word modified is "dumped".
Step-by-step explanation:
The term adverb or adverbial clause refers to a group of words that plays the role of an adverb. In this case, the adverbial clause is introduced by the subordinating conjunction "when". Therefore, the clause is an adverbial clause of time stating when the Tigers dumped the water jug on their coach.