| Term: | Design depth of frost penetration |
| Definition: | (North American usage) the mean of the three largest depths of seasonal frost penetration measured during the past thirty years, or the largest depth of seasonal frost penetration beneath a snow-free soil surface measured during the past ten years (2) (Russian usage) the mean of the depths of seasonal frost penetration measured during at least the last ten years with the ground surface free of snow and the groundwater level below the depth of seasonal frost penetration. |