Rules Index | GM Screen

Hazards and Disasters

Source Ultimate Wilderness pg. 146
The wilderness can be a dangerous place. Monsters roam and hunt within their territories, barbarians protect their settlements with frightening force, and sudden shifts in the weather can overwhelm the unprepared or unlucky explorer. But sometimes the landscape itself presents dangers that dwarf all others. The following are just a few ways that the environment can challenge hapless adventurers in the wild.

Brambles (CR 1)

Source Ultimate Wilderness pg. 146
While many forms of undergrowth can slow explorers, thorny brambles can prove a serious impediment. In addition to functioning as light or heavy undergrowth, brambles damage creatures that move through a space filled with them. The amount of damage taken depends on whether the brambles are light or heavy and what type of armor the creature wears. Light brambles deal 1 point of damage to a creature wearing light armor that moves into their square, while heavy brambles deal 1d4 points of damage to a creature in light armor or 1 point of damage to a creature in medium armor. Creatures in heavy armor don’t take damage from brambles. A creature unwillingly forced into brambles can attempt a DC 15 Reflex save to avoid taking this damage.

Additionally, a creature moving through brambles must succeed at a Reflex save (DC 12 for light brambles, or DC 16 for heavy brambles) or become entangled. Entangled creatures can attempt to free themselves as a standard action with a successful Escape Artist or Strength check at the same DC. A creature needs to attempt this save against being entangled by brambles only when it enters a square of brambles.

A 5-foot square of brambles has AC 5 and hardness 2. A 5-foot square of light brambles has 30 hit points, while a 5-foot square of heavy brambles has 60 hit points. If a square of heavy brambles is reduced to 30 or fewer hit points, it functions as a square of light brambles instead.

Earthquake (CR 9)

Source Ultimate Wilderness pg. 146
Naturally occurring earthquakes result from seismic energy released along fault lines in a planet’s crust. Powerful magic, the release of a legendary monster, or the destruction of a powerful artifact might also result in an earthquake. Earthquakes range from those that are harmless and nearly undetectable to those that are catastrophic and cause widespread destruction and loss of life.

The exact damage of an earthquake is subject to the GM’s discretion. Listed below are general guidelines to assist GMs in running earthquake events. The baseline used here assumes an earthquake of average strength. GMs should modify the values listed depending on the severity of the earthquake.

Earthquakes can have additional effects such as disrupting rivers, draining lakes and marshes, and even triggering tsunamis or volcanic events. Earthquakes might cause widespread fires in urban areas or displace wildlife in wilderness environments. The additional effects should be determined by the GM but should match the strength and severity of the earthquake.

Collapse: Creatures in an enclosed space or underground during an earthquake are at risk of having the ceiling or structure collapse on them. If a structure collapses, each creature inside takes 8d6 points of damage (Reflex DC 15 half ) from the falling rubble and becomes pinned. A creature that takes cover (under furniture, for example) gains the normal bonus for cover on its Reflex save. A creature pinned beneath rubble takes 1d6 points of nonlethal damage per minute while pinned. If a pinned creature falls unconscious, each minute thereafter until it is freed or dies, it must succeed at a DC 15 Constitution check or take 1d6 points of lethal damage. Additional rules for cave-ins and collapses appear in the Core Rulebook.

Falling Debris: Even creatures not in a structure are still at risk of falling debris, whether from a collapsing building nearby or a natural structure such as a cliff or mountain. Any creature caught in the area of falling debris suffers the collapse effects, but it takes 4d6 points of damage at the time of collapse instead of 8d6.

Fissure: Earthquakes can open massive cracks and fissures in the ground. A creature near a fissure as it opens has a 25% chance of falling in unless it succeeds at a DC 20 Reflex save. Additionally, each creature standing in the area when a fissure opens must succeed at a DC 15 Reflex save or fall prone if it avoids falling into the fissure. Fissures are typically 1d4+1 x 10 feet deep, and creatures falling into one take the appropriate falling damage. There is also a 25% chance that surrounding debris also falls into the fissure. Creatures in the fissure when debris falls on them take additional damage from the falling debris. Surviving creatures that are not pinned can attempt to climb their way out.

Impaired Actions: The tremors of an earthquake impose a –8 penalty on Dexterity-based skill checks for creatures on the ground. Spellcasters on the ground must succeed at a concentration check (DC = 20 + the spell’s level) to cast a spell. To move, a creature must succeed at an Acrobatics check; the base DC of this Acrobatics check is 10, but particularly powerful earthquakes and any resulting difficult terrain can increase this DC.

Structures: Most wood or masonry buildings collapse during an earthquake. Structures built of stone or reinforced masonry take 100 points of damage that is not reduced by hardness. Large structures such as castles might not collapse outright, but certain features such as towers or entire sections of a wall might. Creatures caught in a structure that is destroyed suffer collapse effects.

Elemental Influx (CR Varies)

Source Ultimate Wilderness pg. 147
Powerful magic, supernatural disasters, the influence of potent monsters, or the whim of a demigod can cause the boundaries between the Material Plane and an Elemental Plane to wear thin, resulting in an elemental influx that transforms normal wildlands into a dangerous region. Often, creatures such as dragons or other monsters with energy resistances or immunities seek out regions of elemental influx as their domains, and such a creature’s presence can enhance or expand an existing influx.

The following list describes only some of the types of effects an elemental influx might have on the landscape. GMs are encouraged to expand on this list as they see fit.

Acidic Miasma (CR 3): An acidic miasma wafts up from the waters of a swamp infused with toxins leaching in from the Plane of Earth. Exposure to low concentrations of the foul vapors in the swamp causes a mildly uncomfortable burning sensation on exposed skin. Higher concentrations of the miasma are more deadly, usually appearing in pockets 1d6+1 x 10 feet in radius. Upon entering the area of a highly concentrated acidic miasma, a creature must immediately succeed at a DC 15 Fortitude save or become sickened for 1d4 minutes. Creatures that fail the save by 5 or more become nauseated instead. These effects last even if the creature leaves the area of the miasma. Additionally, each round a creature starts its turn in a highly concentrated area of miasma, it takes 1d6 points of acid damage. Highly concentrated miasmas can be identified from 10 feet away by their distinctive stench with a successful a DC 20 Knowledge (nature) or Survival check.

Acidic Plants (CR 3): Acidic plants—usually bushes, mosses, vines, and other undergrowth—are found in clusters with a radius of 1d6+1 x 10 feet. They become active when they are disturbed by creatures moving through their squares. Acidic plants gain a reflexive ability to grab at intruders, and they attempt to grapple creatures moving through their square. The plants have a CMB of +10, and their grapple attempts do not provoke attacks of opportunity. Creatures grappled by acidic plants take 1d6 points of acid damage each round and can’t move without first breaking the grapple (the acidic plants’ CMD is 20). The acidic plants receive a +5 bonus on grapple combat maneuver checks against opponents they are already grappling, but they can’t move or pin foes. Each round that acidic plants succeed at their grapple combat maneuver check, they deal an additional 1d6 points of acid damage. A cluster of acidic plants has AC 10 and 10 hit points. Acidic plants have acid immunity and vulnerability to cold. Burning a square of acid plants causes them to release an acidic gas that spreads in a 10-foot radius; any creature in this gas takes 1d4 points of acid damage. The cloud dissipates in 2d4 rounds unless dispersed earlier by a strong wind or a gust of wind spell. Acidic plants secrete a nearly transparent layer of acid that can be identified with a successful DC 20 Knowledge (nature) or Survival check.

Electrified Duststorm (CR 5): An electrified duststorm begins suddenly, scouring the area in a fierce but short-lived storm lasting 1d6+1 rounds. In addition to the effects of a duststorm, arcs of electricity crackle throughout it. Each round a creature is caught in the storm, it must succeed at a DC 15 Reflex save or take 2d6 points of electricity damage. The onslaught of an electrified duststorm is presaged by a sudden crackle of harmless sparks across the ground 1 minute before it starts and can be identified with a successful DC 20 Knowledge (nature) or Survival check.

Fire Storm (CR 5): Occurring in mountainous areas, fire storms rage with strong winds, raining ash and flame across the landscape. A fire storm usually forms somewhere near a mountain peak and travels downward, but it persists for only 1d6+1 rounds. A creature caught in a fire storm takes 2d6 points of fire damage per round and must succeed at a DC 15 Reflex save or any flammable items that it has catch on fire. Additionally, the ash mixed in with the fire makes the ground difficult terrain and reduces visibility by half, imposing a –6 penalty on Perception checks. Fire storms move quickly, at a rate of 60 feet per round, and have a radius of 1d4x100 feet. A fire storm can be identified as it begins forming over the course of 1d4+1 rounds with a successful DC 20 Knowledge (nature) or Survival check to detect the telltale increase in heat and gently falling ash.

Freezing Eruption (CR 5): Freezing gouts of super-chilled air erupt from small vents in the ground, blasting a 5-foot square with subzero temperatures. A creature occupying the square must succeed at a DC 15 Reflex save to avoid the freezing eruption. On a failed save, the creature takes 2d6 points of cold damage and becomes entangled, as it is encrusted with ice. A creature can break free from the encrusting ice with a successful DC 20 Escape Artist or Strength check, but it takes 1d4 points of cold damage at the start of each turn it remains encrusted. The encrusting ice melts away in 1d6 rounds in regions where the ambient temperature is above freezing. Freezing eruptions occur from the same vent every 1d4 minutes. A square containing a freezing eruption can be identified by the shards of ice around it with a successful DC 20 Knowledge (nature) or Survival check.

Fording a River (CR 2)

Source Ultimate Wilderness pg. 148
In the wild, one cannot count on a handy bridge or access to boats when the need to cross a river arises. While magic such as fly or water walk can aid in the crossing of a river, at other times the traveler has no choice but to attempt to swim, unless the river is shallow enough to cross by wading. Fording a river in this way can be dangerous, especially when mounts or vehicles are involved.

When wading through moving water, a creature must succeed at a Strength check each round to avoid losing its footing and being dragged along by the current. The DC for this check depends on the relative depth of the water and the speed of the current, as outlined on the table below. Deeper water usually has a higher CR, as determined by the GM.

Table 4-6: Fording a River

Condition	Strength Check DC
Water is knee deep	5
Water is waist deep	10
Water is chest deep	15
Water is deeper than creature is tall	20
Per 10 feet/round of curren'ts speed	+2

Attempting to ford a river with a vehicle is similarly difficult, but the vehicle’s driver must attempt a Profession (driver) check rather than a Strength check. Unless the vehicle was specifically designed to be able to travel in water, the driver takes a –5 penalty on this check. If the vehicle is being pulled by one or more creatures, each of those creatures must also succeed at a Strength check to avoid losing its footing, and failure by any creature pulling the vehicle also causes the vehicle to be carried along by the current.

A creature that gets carried along in this way is forced to swim in the water and is moved by the water’s current at the start of its turn each round, as per the normal rules for swimming in flowing water. As long as the creature remains in an area of water where it can reach the bottom, it can attempt a Strength check to catch itself as a full-round action (DC = the normal DC + 5). If a vehicle is carried along by the current, it moves downstream the appropriate distance each round based on the current’s speed, and unless it was specifically designed to be able to travel in water, it takes 4d6 points of damage each round it remains adrift in this fashion.

Some bodies of flowing water are rife with large rocks, logs, and other debris that can prove dangerous to those pulled into the current. In such conditions, a creature or vehicle being moved by the current at a rate of 60 feet per round or more takes 2d6 points of bludgeoning damage per round from such obstacles, plus an additional 1d6 points of damage for every 10 feet beyond 60 that the current moves per round.

Geothermal Spring (CR Varies)

Source Ultimate Wilderness pg. 149
Geothermal springs form where magma heats underground water to extreme temperatures. This hot water periodically erupts at the surface, collecting into pools of heated water of varying temperatures. In some cases, the resulting hot springs are relatively harmless, and communities often pop up nearby, as the therapeutic nature of the spring attracts visitors. But in some cases, geothermal springs are heated to the boiling point or hotter, or they might pose other dangers to the unwary.

GMs should feel free to modify the damage amounts and saving throws of a geothermal spring to take into account the spring’s size and water temperature.

Fumarole (CR 1): Fumaroles occur when the groundwater is boiled away before reaching the surface, so when it erupts from vents in the ground, it does so as steam, often carrying toxic gases along with it. The type of gas released by a fumarole depends on the composition of the surrounding ground. Some fumaroles, referred to as solfataras, emit dangerous levels of sulfuric gas. The eruption rates of fumaroles vary from every few minutes to every few hours.

A creature within 5 feet of an erupting fumarole must succeed at a DC 15 Reflex save to avoid the eruption. On a failed save, the creature takes 2d6 points of fire damage from the scalding steam. If the fumarole emits sulfurous gases, each creature within 30 feet of the erupting fumarole must succeed at a DC 20 Fortitude save or take 1 point of Constitution damage and become nauseated for 1d4 rounds. On a successful save, the creature negates the Constitution damage and is sickened for 1d4 minutes instead of nauseated. This additional effect is a poison effect.

Geyser (CR 3): Geysers form when surface water seeps down into the earth and meets rocks heated by the proximity of magma. The pressure created by the boiling water causes the water to erupt on the surface. The rate, frequency, and length of eruption vary from geyser to geyser. Some issue a single, sustained geyser at a regular interval. Others go through a series of short eruptions, lasting only a few seconds each for hours at a time, and then go dormant for several hours or even days. The jets of water from erupting geysers also vary in height, with some erupting upward of 100 feet in the air.

A creature within 5 feet of an erupting geyser must succeed at a DC 15 Reflex save to avoid the eruption. On a failed save, the creature is knocked prone and takes 2d6 points of fire damage. Creatures immersed in the geyser’s jet each take 5d6 points of fire damage and must succeed at a DC 15 Reflex save or be forced out of the geyser’s jet and knocked prone. Creatures within 10 feet of a geyser (but beyond 5 feet) each take 1d6 points of fire damage from the boiling hot spray falling on them.

Hot Spring (CR 2): Common hot springs contain pools of warm water, but in some, the water is heated to nearly boiling. Exposure to this water deals 1d6 points of fire damage per round. Total immersion deals 5d6 points of fire damage per round; damage continues for 1 round after total immersion, but this additional damage is 1d6 points of fire damage.

Mud Pot (CR 1): Mud pots are springs that mostly contain hot bubbling mud instead of water. The mud’s color depends on the amount and type of minerals in the mud. Mud pots range widely in size and depth, with many found in clusters. Gases from within the earth can cause mud pots to boil over or shoot mud a short distance into the air. Exposure to a mud pot deals 1d3 points of acid damage and 1d3 points of fire damage per round of exposure. Total immersion in a mud pot deals 1d6 points of acid damage and 1d6 points of fire damage per round; damage continues for 1 round after total immersion, but this additional damage is only 1d3 points of acid damage and 1d3 points of fire damage. Moving through a mud pot is like moving through a bog.

Reflective Snow (CR 2)

Source Ultimate Wilderness pg. 149
Glittering fields of fresh snow can pose a danger to unprepared travelers during the daylight hours, as the sun reflecting from the fields of white can be dazzling or even blinding. Travelers through such areas risk having their eyes become sunburned—a condition known as snow blindness. A creature in an area of reflective snow is automatically dazzled, and for each hour it spends in such an area, it must succeed at a DC 15 Fortitude save or succumb to snow blindness, becoming blind for 24 hours. Wearing protective eye gear that reduces the amount of sunlight hitting the eyes negates the dazzled condition and the chance of developing snow blindness. A character can reduce the duration of snow blindness to 1d6 hours with a successful DC 20 Heal check as long as she keeps her eyes covered or wears protective eye gear. Spells such as remove blindness/deafness heal snow blindness immediately. Creatures that are particularly susceptible to bright light take a –4 penalty on saves to resist snow blindness. To a lesser extent, staring out over vast stretches of sunlit water or desert can have the same effects as staring at reflective snow, but the save to avoid blindness in this case is only DC 10.

Spellgorging Plants (CR 1+)

Source Ultimate Wilderness pg. 150
Areas of wilderness devastated by magical battles sometimes regrow vegetation bearing supernatural scars of those conflicts. When the flora in such an area develops a taste for magical energy, the plants and trees display vivid and unusual colors for their type and can even subtly change color. Spellgorging plants thrive on magical energy, making the casting of spells difficult when such plants are nearby. When a creature adjacent to a spellgorging plant attempts to cast a spell or use a spell-like ability, the creature must make a successful concentration check (DC = 20 + the level of the spell) or the spell is lost as the flora absorbs the energy as it is cast. Most magic items are not affected by spellgorging plants, with the exception of spell-completion and spell-trigger items. When such an item is used, the user must attempt a caster level check against the same DC as above but using the item’s caster level instead of his own, in order to successfully use the item.

An area of spellgorging plants can be identified with a successful DC 15 Knowledge (arcana), Knowledge (nature), or Survival check due to the unusual colors and shapes of the surrounding flora. Most animals avoid eating spellgorging plants because of their bizarre and unpleasant taste. A creature consuming a spellgorging plant must succeed at a DC 20 Fortitude save or become sickened for 1d4 hours. A spellgorging plant loses its ability to consume magic if it is destroyed—spellgorging plants have SR 20 for the purposes of resisting magical spell effects, but they otherwise have normal hit points and hardness for plants of their type.

Thin Ice (CR 1+)

Source Ultimate Wilderness pg. 150
A frozen lake or river can prove a serious danger if characters misjudge the thickness of the ice. With a successful DC 20 Survival check, a character can accurately gauge the amount of weight a given sheet of ice can support. Table 4–7: Thin Ice lists the maximum size creature or object that can be supported by ice. (A Fine creature or object can be supported by any thickness of ice.)

When a creature steps onto ice that is one category thinner than what could normally support its weight, the ice begins to creak and crack ominously—a warning that a creature can notice with a successful DC 10 Perception check. At the end of a round, if an area of ice is unable to support its load, it gives way on a result of 10 or less on a d20 roll. This roll takes a cumulative –4 penalty for each size category by which the creature exceeds the maximum size the ice can support. A creature that is prone is treated as one size category smaller than its actual size for the purpose of determining whether the ice can support it. Ice within 5 feet of a fresh break is fragile, and it is treated as one category thinner for the purpose of determining the maximum size creature it can support.

Table 4-7: Thin Ice

Ice Thickness	Maximum Size	Break DC
Under 1 inch	Diminutive	5
1-2 inches	Tiny	15
2-4 inches	Small	20
4-6 inches	Medium	25
6-12 inches	Large	30
1-2 feet	Huge	35
2-4 feet	Gargantuan	40
Over 4 feet	Colossal	50

When ice gives way, a hole of a size equal to the creature’s space opens in the ice. A creature falling into the nearfreezing water beneath the ice is treated as if it were in an area of extreme cold, and on the round it plunges into the water, it must also succeed at a DC 15 Swim check or be submerged beneath the water and trapped beneath the ice, unable to surface. A creature trapped beneath the ice can attempt to break through with a Strength check (the break DC depends on the ice’s thickness, as indicated on Table 4–7), or it can attempt to swim to an opening in the ice (although unless the creature is able to see in the darkness beneath the ice, it might have trouble finding its way to where an opening is). A submerged creature that is adjacent to the edge of the break in the ice can attempt a DC 20 Climb check to pull itself out, although keep in mind that ice adjacent to a break is fragile and could shatter in turn.

Vampire Orchids (CR 3)

Source Ultimate Wilderness pg. 150
Uniquely beautiful in appearance, vampire orchids grow in large clusters in meadows or on hilltops where they can get plenty of sunlight. Their vivid petals range in a hue of wild and clashing colors with frequent splotches of crimson on the petals. Vampire orchids can be exceedingly dangerous to the unwary due to their unusual pollination methods. A creature traveling through a cluster of vampire orchids must attempt a DC 15 Reflex save or a DC 20 Acrobatics check. Failure causes the tremors from the creature’s footsteps to release soporific pollen from the orchids’ blossoms, forcing the creature to attempt a DC 15 Fortitude save to avoid falling asleep for 1 minute. A helpless or sleeping creature takes 1d4 points of damage at the end of each round it remains in contact with vampire orchids— this damage does not cause physical pain and is not in and of itself enough to wake a sleeping creature.

Volcano (CR Varies)

Source Ultimate Wilderness pg. 150
Magma churns beneath the earth’s surface throughout the world, and in places where there are weaknesses in the crust, it can erupt outward in violent conflagrations. Volcanic dangers such as lava, lava bombs, poisonous gas, and pyroclastic flows are covered in the GameMastery Guide, but there are additional dangers that a volcano can present.

Earthquake: The force with which volcanoes erupt can shake the earth, so earthquakes are common during volcanic eruptions. Depending on the nature of the terrain, these disastrous events can cause any of the effects listed in the Earthquake section: they can hinder movement, cause buildings to collapse, open fissures in the ground, and topple structures both large and small. They can also trigger tsunamis.

Lahar: A lahar is a churning slurry of mud and debris created when intense heat melts the glaciers or snow atop a volcano. A lahar can travel hundreds of miles beyond the volcano, devastating everything in its path. Motion alone keeps a lahar in liquid form. When a lahar strikes a creature, it deals the damage listed in Table 4–8: Types of Lahars below (Reflex half, at the listed DC). For creatures caught in a flowing lahar, use the rules for being swept away in flowing water with a DC 25 Swim check. Anyone trapped under a lahar cannot breathe and must attempt Constitution checks to avoid suffocation. Lahars can be hot or cool depending on the events that cause them. A hot lahar deals 2d6 points of fire damage per round to those trapped by it. As a lahar slows, it settles to the consistency of packed earth, entombing those trapped within or beneath. See the Cave-Ins and Collapses section for rules on digging out a buried creature.

Table 4-8: Types of Lahars

Type	CR	Depth	Width	Speed	Damage	Reflex Save DC
Minor	9	10 feet	100 feet	100 feet/round	8d6	15
Typical	10	25 feet	500 feet	250 feet/round	8d6	20
Massive	12	50+ feet	2,500+ feet	500 feet/round	16d6	25

Steam Vent: Major eruptions of steam or boiling water often precede an eruption and deal between 4d6 and 15d6 points of fire damage (Reflex half, DC = 10 + number of damage dice). The radius of such bursts is typically equal to 5 feet per damage die. Mild steam vents are as hot as saunas and have a sulfurous odor.

Volcanic Ash: Erupting volcanoes spew ash, which can obscure vision and cause creatures to choke as if it were heavy smoke. Prolonged contact with hot ash deals 1d6 points of fire damage per minute. Clouds of ash can linger in the atmosphere, darkening the sky for weeks or even months and leading to colder temperatures and prolonged winters. This combination of cold and lack of sunlight hurts crops, and it can cripple food supplies and lead to famines. On the ground, ash buildup creates difficult terrain—not only is it slippery, but it might conceal other hazards. In heavy eruptions, a blanket of ash several feet thick can eventually blanket the region downwind of the volcano. Over the long term, however, this volcanic ash becomes fertile soil.

Volcanic Lightning: Ash clouds can generate powerful lightning strikes. These strikes typically deal between 4d8 and 10d8 points of electricity damage and are unusually difficult to dodge (Reflex half, DC = 15 + number of damage dice).

Archives of Nethys

Rules Index | GM Screen

Table 4-6: Fording a River

Table 4-7: Thin Ice

Table 4-8: Types of Lahars