* Snow Density: Freshly fallen snow is very fluffy and has a low density. As it settles, it compacts, and its density increases. This means the same amount of snowfall can result in different depths depending on how much it has been packed down.
* Wind: Wind can blow snow around, creating drifts in some areas and leaving other areas relatively bare. This can significantly alter the depth of snow on the ground.
* Terrain: The shape of the land affects snow accumulation. Snow tends to pile up more in hollows and on the lee side of hills.
In short: A foot of snowfall might result in a few inches of snow on the ground, or it could lead to a foot or more of snow depending on the factors mentioned above.
