Hoar Frost
Lethal creeping cold pervades—deadly to warm flesh, covering objects in frost, instantly freezing even boiling water, and making the eyes sting as bodily fluids try to solidify into thin layers of ice.
Fires. Both mundane flame and arcane heat can stave off the building frost, but maintaining any fire requires constant vigilance with 2 (1d4) ongoing fire damage at the end of every 10 minutes (for flames kept alight with cantrips) or a Survival check once each hour.
Frozen Solid. Keeping one’s belongings relatively warm is paramount. Each day 4 (1d4+2) Supply becomes useless as it freezes solid—waterskins burst and leak when their contents melt and provisions crumble when thawed.
Lethal Cold. At the end of every hour in the area, creatures take 3 (1d6) cold damage. Wearing cold weather gear (see Survival Gear ) halves this cold damage (minimum 1). No short or long rests are possible in the cold. A creature reduced to 0 hit points can become stable, but only after it is wrapped in furs and blankets or placed adjacent to fire to protect it from the cold—otherwise it continues to suffer from the cold while in the area, making additional death saves when dealt cold damage.
Keep Moving. To prevent frostbite an adventurer needs to keep moving, stay wrapped in warm garments, and expose as little flesh as possible. Any stationary objects become covered in thick layers of ice and freeze solid (this includes tents or spells that create solid surfaces.)
The party needs to make a group check to get through the region. Adventurers can choose from the following:
- Engineering checks to create improvisational structures that allow the party to safely stay warm.
- Medicine checks to treat frostbite. This may be necessary to prevent the loss of fingers and toes.
- Survival checks to locate shelter that will stay warm enough for safety.
- Constitution saving throws to simply power through.
Potential Outcomes
Critical Failure: The party loses 2 (1d4) days of travel time and suffers one level of fatigue navigating through the area. In addition, a pocket of warm air from far above suddenly condenses and falls in a soaking slush, forcing each adventurer to make a Strength saving throw or be restrained as the liquid transforms into ice that encases their body. A restrained adventurer takes 16 (3d10) ongoing cold damage until they are freed with a Strength check. The ongoing damage also ends if the encasing ice is destroyed (AC 16, 20 hit points, and immunity to cold damage). Any adventurer that takes 30 or more cold damage suffers an additional level of fatigue.
Failure: The adventurers lose 1 day of travel time and suffer one level of fatigue navigating through the area.
Success: The adventurers manage to push through the area.
Critical Success: Roll on the Boons and Discoveries table.