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 are commonly from frost tube instruments, visual reports from construction or cemetery sites, or other types of electronic probes. Frost conditions are an important factor for hydrologic forecasting as frozen soil limits infiltration of water thereby generating more runoff from rain and snowmelt than soil that is not frozen. Knowing soil frost condition is also important for many activities including agriculture, horticulture, transportation, construction, and even grave digging.
Links to some additional information about frost depth and soil temperatures: