This spell can be cast on a water-based terrain feature such as a river, swamp, marsh or lake; that terrain feature is permanently frozen and treated as open ground from now on. All models in the terrain feature when the spell is cast take a Strength 2 hit with no Armour save.

Alternatively, this spell can be cast on a single unengaged enemy unit within line of sight. The target unit moves as if in difficult terrain in its next Movement phase.