Some areas of terrain are incredibly treacherous and present a very real risk to life and limb.
When a model marches, charges, flees, overruns or pursues into or through an area of dangerous terrain, it is called upon to take a Dangerous Terrain test – roll a D6. On a 2-6, the model successfully negotiates the dangers of the terrain and reaches its destination safe and sound. If a 1 is rolled, however, the model has suffered a terrible mishap and suffers a wound with no armour saves allowed.
A mounted warrior has many advantages over their footslogging comrades, but does risk being thrown from the saddle when riding at speed. A galloping horse can trip on a tree root, hurling the rider into a boulder, or can duck low under a branch, but alas not quite low enough for the rider... As such, cavalry, monstrous cavalry, chariots and shrines treat all terrain other than open ground as being dangerous terrain, as described above. A chariot or shrine that fails a Dangerous Terrain test suffers D6 Wounds instead of 1.