The salt mountains, a.k.a. "sinking through stuff"

We were at some sort of salt hot water spring, streaming down a hillside like a big water slide with thrilling waterfalls. We slid down the stream, surrounded by slopes full of salt, looking like a thick layer of snow. Once we reached the end I started walking forward in the salt and the others followed me. But all of a sudden I started sinking through it, deeper and deeper. It seemed bottomless. Until finally I broke through the roof of some sort of underground cottage. The others came down with me. The inside looked like a big sauna, with an adjacent room with what looked like a sea of small bags of cat food. I noticed that one of them were opened and that some food were spread around it, as if someone had been there recently, eating from it. I started wading through the sea of food bags when all of a sudden I started sinking again, feeling the bags envelope me.