Whether a soil above the 250 isoline is prone to frostheave depends on its soil moisture regime and tex-ture class. Family texture classes are assigned bysoil moisture regime to the three frost action classesin exhibit 618–5 in the National Soil Survey Hand-book. Climates that have little snow cover overwinter, ample fall and winter precipitation, andseveral freeze and thaw cycles increase the inci-dence of frost heave damage