after the hurricane, the river was once again tranquil. it was hard to believe that only hours before it had been wild and dangerous.

before가 전치사로 쓰인게 맞나요? 또, it 은 hurricane을 지칭하는게 맞나요??
그렇면that 절 이하에서 주어가 only hours인 것 같은데해석이 깔끔하지가 않아요
설명 좀 부탁드릴게요~