Just thought I'd share my recent experience of a flash flood at Pine Valley on 10 March - unfortunately i don't have any photos, it was all a bit too exciting to stop for a kodak moment. Another thread referred to the thunderstorm that afternoon, but not to the flash flood we had in the valley.
We were up in the Labyrinth as the storm was developing up on the peaks, and half an hour after we got back to the camping area the rain started falling heavily and continued for a couple of hours, but not in a quantity or quality i would have expected to produce what followed. Just on dusk, water levels in the creek rose rapidly from a mere stream to a raging torrent covering the whole valley floor below the hut under the myrtles about 10 mins later. We were very lucky that the water in the creek 'rose' rather than came down in a wall, otherwise several of us may not be here to tell the tale. Also that it happened in daylight. Would have put this up sooner, but i've been on holidays.

It was a good lesson for me, I'll never pitch my tent near a creek bed again, (even if it was unusual conditions, I guess being so dry the water wasn't absorbed and just came rushing down). But there was a silver lining. In the rush to save my belongings, I had to abandon my lovely Hilleberg tent to the flood. As dark fell I watched water engulf it and I was sure I would never see it again. Next morning, however, there she was, rather wet and dirty on the outside, but absolutely fine, not one tent peg lost. That's one good tent.