Poisonous Snowfall (CR 2)

When a creature ends his or her turn beneath this hazard, have that creature make a DC 15 Stealth check, modified for distance (assuming the hazard is 20 feet above the ground). Assume that PCs unaware of the danger are taking 10 on their Stealth checks, but are moving at normal speed, thereby also receiving a –5 penalty on these checks. A character who gets below 15 on this Stealth check causes a clump of poisonous snow to fall in each square of a circular area centered on the character. The circular area has a diameter of 5 feet for every point the Stealth check failed by, and for every 5 points the Stealth check fails by, an additional clump of snow falls in the character’s square. A character in a square of falling snow who is aware or suspicious of the danger it presents may make a DC 15 Reflex save to prevent being struck by the snow and exposed to a dose of poison.

Each additional clump falling in a square in a round increases the DC of this Reflex save by 2. Fortunately, however, each hazardous square only has a total of 1d4 clumps of snow, limiting the amount of snow that can fall. Creatures with cover or those covering themselves (for example, with a shield) gain a +2 bonus on this save.