First comment: I'm way up north and we've got plenty of water in the water table, the biggest lake in the world about 200 yards from where I sit, and 4 feet of snow on the ground at the house. Therefore I might not have my story straight.
At the GNRS last weekend I was chatting with an EM racer, and he talked a bit about the need for moisture there. He mentioned something that I didn't know -- that just plain rainfall on the dirt isn't nearly as good as a nice, long-term soaking rain on the entire area around the lakebed is what's needed. He described it as this: It's not just moisture that'll help fix the dirt, but the fact that the runoff from neighboring mountains and highlands will bring minerals down to the dirt. Those minerals are what the dirt lacks right now, and what must be put back in before the surface will begin to heal.
Rain on the lakebed might help make the dust stick together for a short time, but the minerals in the water from around there are what's needed to make it get better at E.M.
That's it for me -- back to snow removal.