Terrain Combat Modifiers

[Jagger]

Yes they do, but be aware that the effect of a hexside does only come into play the turn after a unit has moved into the hex that is adjacent to the hex side.
For example, a Rebel unit that moves into a hex that has a fence between them and the enemy will only benefit from the fence the next turn.

So creek and stream terrain modifiers have an impact on fire results but not immediately upon arrival in the hex.  Thanks!