Sorry for multiple posts. I had played with it more and compared the results with a simple 1D model. The water surface elevation in the result file is the same as open water condition. The bottom of ice and top of ice appear to be the same and ice thickness is zero. I wonder if there is anything I need to modify in the ice_cover example files. I see that in the validation document, Figure 4.2 is also showing the water surface being the same as equivalent free surface, top ice cover, as well as bottom ice cover. I am wondering if these examples of "presence of ice cover" are not really working the way they suppose to.