Raging Forest Fire
COMPLEX HAZARD 1A successful DC 15 Athletics, DC 15 Nature, or DC 15 Survival check from an adjacent square is sufficient to smother one 5-foot-square of fire; each attempt is an Interact action. Dousing the flames automatically extinguishes one or more sections of fire, with no check. Water typically clears a 5-foot square if the amount is small (such as that from Create Water or Hydraulic Push). Larger amounts of water, such as a full bucket, typically douse a 10-foot-by-10-foot area (or 4 squares in some other shape). Throwing a bucket of water on flames requires an Interact action. A Waterskin doesn't contain enough water to put out even 1 square of fire.
Cold can also put out fire, but only if the cold can affect an area; cold is usually less effective than water, so a Frost Vial typically puts out only 1 square of fire, and Ray of Frost is ineffective.