Narrow valleys in Judah were dry most of the year until a sudden, heavy rain turned them into fast-moving water. When that happened there was a lot of noise and wind. (See: [[rc://en/ta/man/translate/figs-simile]])
Yahweh speaks of himself by name to express the certainty of what he is declaring. Translate as in [Isaiah 30:1](../30/01.md). AT: "this is what Yahweh has declared" or "this is what I, Yahweh, have declared" (See: [[rc://en/ta/man/translate/figs-123person]])