Terrain Thralls has a photo tutorial on making terrain that looks like ice floes. They’re cleverly made from foam core, and is intended for Privateer Press’ Warmachine game, but I think it would be spectacular in a variety of fantasy settings. I can also envision a neat Frankenstein vs The Monster scenario.
This video on adding snow, ice and sludge to your wargaming terrain. Useful stuff for the currently popular Frostgrave rules.