AbstractWhen large masses of ice, for example in the form of glaciers or floating ice fields, are moving against an obstruction, either natural or man-made, huge forces will develop. It is possible to derive formulae to estimate these forces from elementary mechanics of the rupture of ice. The basic formula may be written: F = ϕ(C)rced, where ϕ(C) is a function of the geometrical and physical parameters of the system, rc is the compression strength of the ice, e is the thickness of the ice, and d is the width of the structure. The paper deals with the different types of rupture patterns that may develop in front of either vertical or inclined faces, and formulae are given for some typical cases.