Abstract: An explosive device for use in removing ice formed in railroad tunnels and similar underground cavities comprising a base member and mating cap member assembled to form a rigid blast-directing assembly having a groove formed around its periphery at the juncture between the base and cap members, and a ring-shaped explosive substance, detonable by an electric charge, seated therein. The peripheral groove is of sufficient depth and width that any explosive gases and heat produced therein will be directed radially outward from all sides of the assembly in a relatively thin, fan-like pattern. In use, a plurality of the devices are fastened in clusters to the interior wall and ceiling surfaces of a railroad tunnel or other underground cavity at those points where water seeping into the cavity is likely to freeze into ice.