Frost line
From Glossary of Meteorology
frost line
Maximum depth of frozen ground during the winter.
The term may refer to an individual winter, to an average over a number of years, or to the greatest depth since observations began. The frost line varies with the nature of soil and the protection afforded by vegetal ground cover and snow cover, as well as with the amount of seasonal cooling.
Compare frost table, permafrost table.
Compare frost table, permafrost table.
