before before before

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~