Travelling to Wisconsin for Garycon in early March brought up an interesting trap idea. Weather acts much like a trap in overland adventuring. With this in mind, let's talk about weather and traps.
Inclement weather of most kinds can be used as a trap of sorts. Icy conditions on the ground can cause someone to fall. Torrential rain or snow can obscure vision. Even high winds can force a travelling group off their compass heading. All of these mimic traps in one form or another.
Today, I will start with ice. Ice on the ground can be nearly invisible. Ice storms hurt. If you have ever been in an ice storm, you know the stinging pinch of hard water welting your skin. And as it hits the ground, it becomes more and more treacherous to just walk.
An icy patch may just be a singular hazard along a forested trail, or there may be a sequence of them. Patches of ice can be almost anywhere. A patch can have wildly different consequences based on that location. Wherever one is, it should to be adjudicated as a trap. As I have talked about previously, this event is a lot more fun if the characters can interact with it. Detecting it (even if it is "black ice") should be easy enough. Rangers, druids and thieves (rogues if you prefer) should be able to find the icy patch with their miscellaneous abilities. Getting through or around the ice may be a different story.
Are they on a high mountain pass, with granite on one side, and air on the other? How do they navigate the ice then? They will come up with a creative solution.
Are they in the middle of a crowded city? They may not be able to avoid the ice. In this case falling down may only hurt their social status. (And it can be used as a comic relief moment.)
How would I actually put rules to these ideas? For OSR games, I would probably force a saving throw for attempting to cross. Depending on the system used, it could be Dexterity based or Paralysis.
I may give barbarians, rangers or other characters bonuses depending on their background and experiences. For a more modern game, I would probably use a straight dexterity check. Whatever system I use, I would add bonuses for creative ideas. Using a walking stick might garner a +1, but making a walker with 4 legs might gain a +8.
Ice storms are a much different obstacle. In addition to the effects above, an ice storm will probably halt overland travel. A storm could force a caravan (or group of adventurers) off their compass heading. And pelting ice should cause damage.
Whatever system I use, I would cause 1d6 damage per 10 minutes of travelling in an ice storm. Tents are not much protection in these circumstances. After the tents are up, I would have everyone take 1d6 every half hour. Spurring a mount forward in an ice storm is dangerous. In addition to the damage, a mount may slip, breaking a leg or causing another injury.
If the group is not on a road, getting lost travelling through an ice storm becomes likely. An OSR group wants a ranger in these circumstances. Adjudicating much like surprise, a ranger would be lost only 1 in 6. Druids and Barbarians only 2 in 6. Everybody else 4 in 6. These numbers can be adjusted for familiar terrain or other factors.
In a modern game, Survival skill check would determine if the group is lost.
Weather as a trap is a strong concept in D&D. It adds some realism to an overland journey and can make fun encounters without being deadly. Over the next couple of weeks, I expect to revisit the idea with other inclement weather types.
See you in the dungeon halls,