If new solar toilets were installed, the availability would probably be just like it was for the 30 some yrs that the old ones were in operation. A modern design can easily hold the small use that occurs in the early and late season. Actual composting and evaporation would then catch up in the warm months exactly when the use also picks up. For the few hearty climbers in the winter, this would be like any other place in the Sierras, you have to pack it out, the toilets might be buried in snow. No different than anywhere else.
