Again we cross a white, battered gully, the pathway of rock avalanches or snow avalanches.

我们再次穿过一个白色的、破旧的沟壑，这是岩石崩塌或雪崩的路径。

Then I was startled by a sudden thundering crash as if a rock avalanche had come to the help of the roaring waters.

然后我被突然的雷鸣般的撞击声吓了一跳， 就好像一场岩石崩塌帮助了咆哮的海水。