Frozen ground is one of the most difficult things to deal with during construction projects. Curing, roofing, concrete pouring and digging all become hard and impossible to do if the ground is frozen.
It takes five days of freezing temperatures for the soil to freeze solid, but that’s not necessarily the case for all areas. Different factors influence this process, such as the type of soil, water content, density and amount of snow in the area.
The ground freezes because water in the soil freezes. When the temperature drops below 0°C (32°F) water that is in soil pores, rock cracks and other fractures freeze.
During the fall, the soil may have dried up a lot. This can make the frost level lower and the water lines deeper.
When the temperature falls below 0°C (32°F) a meter (a few feet) underground, water that is in soil freezes. The temperature of the surface layer of soil may also be lower than the air above it.
Soils that are lighter in color freeze sooner and deeper than dark soils. They also reflect sunlight, making the surface colder.
Seasonally frozen ground typically freezes and thaws once per year. Permafrost, on the other hand, is frozen ground that stays frozen all year. More than half of the land in the Northern Hemisphere is seasonally frozen, while about one-fourth of it has an underground layer that remains frozen all year long.