Additional Modifiers: For tundra, magma crust, deep snow and mud hexes, apply a –1 modifier to the Piloting Skill Roll to determine whether a unit entering such terrain gets stuck. Apply the same modifier to Piloting Skill Rolls made to free a stuck unit.
Infantry: For infantry entering such a hex, roll 2D6. On a result of 4 or less, the unit gets stuck. To escape getting stuck, an infantry unit need only make a 2D6 roll of 4+.