If any part of a unit moves through difficult terrain, that unit suffers a -1 modifier to its Movement characteristic (to a minimum of 1). This modifier is applied whether the unit begins its movement in difficult terrain, passes through difficult terrain during its movement, or ends its movement in difficult terrain.

In addition, a unit that ends its movement with a quarter (25%) or more of its models within difficult terrain (or straddling a low linear obstacle, below) becomes Disrupted.