The rainy season on the salt flats finishes by early autumn (late March) on the Uyuni Salt Flats. This means that some areas are still covered by 3 - 4 cm / 1-1/2 inches of water (brine really) while other areas have started to dry out.
I tried to capture this wet / dry interface in this shot, perhaps not totally successfully. The brilliant blue skies and the clouds can be seen reflected in the brine, but there lots of areas of salt crystals forming that break up the wet areas and add specular highlights. In the foreground, I am standing on a thick crust of white salt crystals.
The altitude here was reasonably "low" when compared to much of the rest of Bolivia, a mere 3680m / 12,100 ft. It makes sense as the area is a depression where the rain water gathers.
At times it looked like we were walking on wet ice but wet salt is not slippery at all.