Montana-Frost-Line-Map. Back To Map Montana Extreme Frost Line Penetration (in inches) State Average Frost Depth: 61″. Source: U.S. Department of.
The frost line is simply the deepest point in the ground to which ground water will freeze. The frost line map below was drawn based on data from the U.S Department Montana Nebraska Nevada New Hampshire New Jersey. New Mexico.
Frost depth data shown in this map is queried from the North Central River Forecast Center (NCRFC) database late morning each day. Frost depth reports here.