How do solution cavities create salt karst topography on a playa?

On a playa, salt karst topography develops when thick, soluble salt crusts undergo dissolution due to fluctuations in the water table.2

Because rock salt is impervious, solution occurs exclusively on its exterior surfaces. The process requires that the brine formed by this initial dissolution be drained away by groundwater to allow further erosion to continue. As water percolates down toward the water table, it creates solution cavities within the salt crust. Depending on the thickness of the salt body, these cavities can evolve into various features, including sinkholes, caverns, and crevices, which collectively form the rugged landscape known as salt karst.12