There is no answer to this question; it depends on a variety of issues, the biggest of which is the thickness of the ice. One square foot of one inch thick ice weighs significantly less than one square foot of one foot thick ice. The other factor involved is the density of the ice. The biggest factor here is the amount of air trapped in the ice. Temperature and air pressure can also affect ice density. The Dr. Math Forum addressed this issue in one of their postings. See the Web Links to the right for a link to their discussion.