Collapsing Bridge
HAZARD 6 +25 (or 0 if a PC has analyzed the supports and discovered they are on the verge of collapse)
As a pillar collapses, the bridge itself groans and shakes, then crumbles into the river below.
Several weeks of repair can rebuild the supports and remove the danger; at the GM's discretion, spells like Wall of Stone or Wall of Force can be used to augment the supports more quickly, although these spells are likely out of reach of the PCs at this point.
AC 21; Fort +9, Ref +9
Hardness 10, HP 58 (BT 29) For each support; Immunities critical hits, precision
Collapse
A support is destroyed
The bridge collapses. Any creature on the bridge between the red dotted lines falls 30 feet into water or onto land, taking damage as appropriate plus an additional 5d6 bludgeoning damage (DC 24 basic Reflex) from falling debris; a creature within five feet of the red dotted line can try to Grab an Edge (DC 24 Reflex) to avoid falling. A creature under the bridge-either directly below it or within ten feet of it-must attempt a DC 24 Reflex save; a creature that's not directly under the bridge improves the result of their saving throw one degree.
Critical Success The creature takes no damage.
Success The creature takes 2d8 + 9 bludgeoning damage.
Failure The creature takes 4d8 + 18 bludgeoning damage and is knocked Prone.
Critical Failure The creature takes 8d8 + 18 bludgeoning damage, is knocked prone, and is Immobilized by fallen rubble from the collapsed bridge.
Pathfinder KingmakerOGL