Sometimes wandering the frontier battling bandits and fighting abominations are easier than fighting Mother Nature herself. The following are a bunch of environmental encounters for the Posse to overcome to get where they are going. A note to the Marshal, some of these encounters might not be appropriate depending where the Posse is or what time of year it is.
While traveling the in the wilderness the Posse encounters a narrow stream or river. The ice cold water of the stream is moving very fast and the bed it very rough and slick. The stream could be a winter thaw runoff surge or perhaps the it is a mountain river rapids. Describe the river as very dangerous looking with jagged rocks jutting out of white water and deep eddies that threaten to pull a man under and keep him their.
To cross the stream/river where they encounter it the characters and/or their mounts need to make Agility rolls at a -4 if they decide to cross at the point they encountered the stream. Characters may choose to ride their horse across using a Riding roll both themselves and the mount instead of Agility rolls.
The players can also decide to find a better place to ford the stream/river. Have them make a Survival (or Knowledge: Area with a + 2 to + 4) roll with + 1 bonus for every hour they spend looking for a better place to cross. On a standard success, the penalty to cross is reduced to a -2. With a Raise, the Posse can cross with no penalty. With 2 or more Raises the Posse located a spot that calm enough to cross without a roll, find a boat, rough bridge, etc.
Characters that fail their Agility or Riding check must then make a Swimming roll to avoid the rocks and eddies. The character needs to get a Raise to make it to one side of the stream or other (505 chance either side). A standard success on the Swimming roll means the character has avoid the rocks but is swept down stream another 6". Failure results the character being swept down stream 6" in 1 level of Fatigue from bumps and bruises as they crash upon the rocks, A roll of less than 1 means the character is caught in an eddy and is being pulled under the character can continue to make swimming rolls or be assisted by fellow Posse members to pull them out reach round they must make a Vigor roll to avoid another level of Fatigue to avoid drowning. Rolling snake eyes on the Swimming roll means the character has got their foot caught and the swiftness of the water is keeping their head below water. They need to make a Strength check at a -2 to free themselves as well as a Vigor check each round to avoid drowning (or breaking their leg with a botch). Posse members can only assist by risking themselves by jumping in the rapids as well.
The trail leads into steep mountainous terrain. The Posse needed to complete a Climbing or Strength to pull themselves up mountain side, Vigor or Survival rolls for fatigue and Mountain Winds, Agility or Riding Checks to make it back down. Failure means the posse spends an entire day attempting to find a better route. Draw a card each day, if a Clubs is drawn a complication happens. Example Complications: Impassible route (automatically lose a day backtracking), Severe Weather (Vigor rolls for exposure), Rock slide (Agility roll to avoid 2d10 damage), Lost footing (Climbing roll to themselves back onto best route).
For whatever reason, hunting and foraging is remarkably bad in this region at the moment. All survival rolls are made at -4 to secure food.
Dense Forest/Increasingly Rough Terrain
The wilderness seems to be against the Posse as the forest thickens or the scab lands become near untraversable. The Posse needs to make a Boating, Survival, Knowledge: Area roll to avoid becoming lost. Even with success, the trip takes twice as long to find a trail to continue to travel.