Frost line depth in Petroleum County, MT

How deep the ground freezes in Petroleum County, MT

48 in. Dig to 48 in, just below the frost. Nearest NOAA station: Valentine, 18.7 mi.

Your building department sets the legal frost line depth (IRC Table R301.2(1)); footings must go below it (R403.1.4.1). Call them before you dig.

Code depth · Method