The metastable state of water extends to –39°C. Icing on solid surfaces does not need such supercooling of water. The necessary water supercooling depends mainly on the material of the solid body and the roughness of its surface. The presence of a large number of micro-roughnesses of various form and size causes the simultaneous appearance of many crystals the growth of which leads to the formation of the primary ice layer. The shape and orientation of crystals of the primary ice layer on a solid surface are determined by the material and structure of the solid and by the surface roughness. The number of crystals on the unit surface N = A × 10^{K ΔT}, where A and k are coefficients determined by solid material and surface roughness and ΔT is the water boundary supercooling. The growth of the primary ice layer is followed by an increase of cross-section of some crystals at the expense of the contraction and disappearance of the other ones. The greater the supercooling of the water and the higher the temperature gradient of the ice layer the greater the growth rate of crystals. Under high temperature gradients most of the crystals have their axes directed parallel to the freezing surface. With low temperature gradients and lower supercooling the crystals have a fabric with c-axes directed perpendicular to the surface of freezing.

Knowledge of these features of ice formation processes makes it possible to solve the problem of ice formation with a planned structure and strength and to forecast the structure and strength of ice on structures.