I do have two raster layers (interpolated with Empirical Bayesian Kriging), that show the elevation of a glacier in April, and September. I want to show the change in elevation between the layers in water equivalent. Any suggestion on how I can do that?
I'm not sure what you mean by "water equivalent". If you're just wanting to find the difference between the two rasters, it's a simple matter of subtracting the two in Raster Calculator.
Your expression will look something like this:
You will need the Spatial Analyst extension.