depending on what type of soap it can dry out your bases, just like it dries out skin.
to OP, If you have turf to lay over a wooden ramp, i would really suggest using a wooden ramp. just lay your turf down on the wood lip and lay your snow over that, that way you won't waste snow using it for the base of the lip, and when the snow starts to melt, it leaves a film of slush on the turf that makes the turf slide a lot faster than it usually slides. this has seemed to work well in the past for me.