the.com/frost line
the underground border between soil that shrugs off winter and soil that doesn't.
means the depth to which groundwater in soil freezes, and the reason building codes tell you how deep to dig your foundation.
from a civil engineering and agricultural term formalized as regions mapped how deep freezing penetrated soil each winter, since anything built above that depth risks heaving as ice expands.
depth rangezero in florida, over 100 inches in alaska
foundation rulefootings must sit below it, always
frost heaveice lenses can lift structures inches upward
pipe burialwater lines buried below it to avoid bursting