When the temperature drops below freezing, moisture in the pore spaces between sand grains turns to ice. Unless there is very little water in the sand (<0.5% moisture content), the pore ice binds the sand grains together. The result is a frozen, cemented surface which feels as solid as concrete.

The strength of the frozen ground depends on temperature and the amount of moisture present. Colder temperatures and higher moisture contents increase the strength of the pore-ice cementation.

The cementation immobilizes the sand grains even under the forces of the strongest winter winds. The cohesion produced by frozen moisture is much greater than the cohesion resulting from moisture alone.