Friday Encounter: Thin Ice

Here's another Friday Encounter based on a favorite theme of mine - interesting environmental obstacles that present logistical puzzles to overcome. It is suited to a wilderness location or on the road in wintertime or in a cold climate, or potentially in a thematically appropriate dungeon.

The PCs' path forward should be blocked by a frozen river, lake, or other body of water sufficiently large such that circumnavigating it would be a non-trivial task. A DC 10 Survival check will determine that the ice is thin, and would break easily if sufficient weight was put on its surface.

Any creature that attempts to cross the ice must make a DC 20 Stealth check (to represent tiptoeing carefully across the surface) or risk breaking the ice. Creatures carrying more than 30 pounds of equipment (including worn items) have Disadvantage on this check, and those carrying more than 60 pounds fail it automatically. Creatures of Large size or greater also automatically fail the check. Creatures under a feather fall spell or similar effect automatically pass the check, as they are unnaturally light.

If a creature fails the check, the ice splinters underneath their feet and splits open into the freezing cold water below! The creature must then make a DC 15 Dexterity saving throw to try and jump away from the breaking ice. If that save is failed, they plummet into the water. They must then make a DC 15 Constitution saving throw. On a failed save, they take 2d12 cold damage and one level of exhaustion; on a successful save, they take half damage, but still take the level of exhaustion. If a creature manages to dodge the ice breaking, they may be able to jump to the other side of the ice, or they may need to repeat the process multiple times before the ice is crossed, depending on the DM's choice.

Once a creature falls into the water, enter Action Time. The creature that fell into the water gains the Stunned condition for one round. After the first round, they gain the Restrained condition until pulled onto dry land, and must make a DC 15 Constitution saving throw at the beginning of each of their turns, taking 1d10 cold damage for every failed save. They may attempt to curl into a ball to conserve heat; if they pass a DC 17 Survival check, they gain Advantage on all subsequent Constitution saves until pulled onto dry land. Optionally, they may also sink five feet into the water at the beginning of each turn, depending on how deep it is.

The idea here is to force the party to confront a situation that can't easily be solved by throwing class abilities at it (well, unless your wizard knows how to levitate people). If the PCs want to cross the ice, they might need to leave treasure, horses, heavy armor, or other heavy assets behind, which may limit their resources if they run into anything on the other side. They may also decide it's better to spare the trouble and go the long way around, but who knows what challenges might be that way! A really clever party could even use the ice to their advantage - for example, luring pursuers over the ice to force them to break the ice and fall through. As always, it's best to leave it to your players to figure out a solution, and use your judgment on whether or not it should work based on sound logic.