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Wilderness

Source PRPG Core Rulebook pg. 424
Outside the safety of city walls, the wilderness is a dangerous place, and many adventurers have gotten lost in its trackless wilds or fallen victim to deadly weather. The following rules give you guidelines on running adventures in a wilderness setting.

Getting Lost

Source PRPG Core Rulebook pg. 424
There are many ways to get lost in the wilderness. Following an obvious road, trail, or feature such as a stream or shoreline prevents most from becoming lost, but travelers striking off cross-country might become disoriented—especially in conditions of poor visibility or in difficult terrain.

Poor Visibility: Anytime characters cannot see at least 60 feet due to reduced visibility conditions, they might become lost. Characters traveling through fog, snow, or a downpour might easily lose the ability to see any landmarks not in their immediate vicinity. Similarly, characters traveling at night might be at risk, too, depending on the quality of their light sources, the amount of moonlight, and whether they have darkvision or low-light vision.

Difficult Terrain: Any character in forest, moor, hill, or mountain terrain might become lost if he moves away from a trail, road, stream, or other obvious path or track. Forests are especially dangerous because they obscure far-off landmarks and make it hard to see the sun or stars.

Chance to Get Lost: If conditions exist that make getting lost a possibility, the character leading the way must succeed on a Survival check or become lost. The difficulty of this check varies based on the terrain, the visibility conditions, and whether or not the character has a map of the area being traveled through. Refer to the table below and use the highest DC that applies.
TerrainSurvival DC
Desert or plains14
Forest16
Moor or hill10
Mountain12
Open sea18
Urban, ruins, or dungeon8
SituationCheck Modifier
Proper navigational tools (map, sextant)+4
Poor visibility-4

A character with at least 5 ranks in Knowledge (geography) or Knowledge (local) pertaining to the area being traveled through gains a +2 bonus on this check.

Check once per hour (or portion of an hour) spent in local or overland movement to see if travelers have become lost. In the case of a party moving together, only the character leading the way makes the check.

Effects of Being Lost: If a party becomes lost, it is no longer certain of moving in the direction it intended to travel. Randomly determine the direction in which the party actually travels during each hour of local or overland movement. The characters’ movement continues to be random until they blunder into a landmark they can’t miss, or until they recognize that they are lost and make an effort to regain their bearings.

Recognizing You’re Lost: Once per hour of random travel, each character in the party may attempt a Survival check (DC 20, –1 per hour of random travel) to recognize that he is no longer certain of his direction of travel. Some circumstances might make it obvious that the characters are lost.

Setting a New Course: Determining the correct direction of travel once a party has become lost requires a Survival check (DC 15, +2 per hour of random travel). If a character fails this check, he chooses a random direction as the “correct” direction for resuming travel.

Once the characters are traveling along their new course, correct or incorrect, they might get lost again. If the conditions still make it possible for travelers to become lost, check once per hour of travel as described above to see if the party maintains its new course or begins to move at random again.

Conflicting Directions: It’s possible that several characters may attempt to determine the right direction to proceed after becoming lost. Make a Survival check for each character in secret, then tell the players whose characters succeeded the correct direction in which to travel, and tell the players whose characters failed a random direction they think is right, with no indication who is correct.

Regaining Your Bearings: There are several ways for characters to find their way after becoming lost. First, if the characters successfully set a new course and follow it to the destination they’re trying to reach, they’re not lost anymore. Second, the characters, through random movement, might run into an unmistakable landmark. Third, if conditions suddenly improve— the fog lifts or the sun comes up—lost characters may attempt to set a new course, as described above, with a +4 bonus on the Survival check.

Forest Terrain

Source PRPG Core Rulebook pg. 425
Forest terrain can be divided into three categories: sparse, medium, and dense. An immense forest could have all three categories within its borders, with more sparse terrain at the outer edge of the forest and dense forest at its heart. The table below describes in general terms how likely it is that a given square has a terrain element in it.
Category of Forest
SparseMediumDense
Typical trees50%70%80%
Massive trees10%20%
Light undergrowth50%70%50%
Heavy undergrowth20%50%

Trees: The most important terrain element in a forest is the trees, obviously. A creature standing in the same square as a tree gains partial cover, which grants a +2 bonus to Armor Class and a +1 bonus on Reflex saves. The presence of a tree doesn’t otherwise affect a creature’s fighting space, because it’s assumed that the creature is using the tree to its advantage when it can. The trunk of a typical tree has AC 4, hardness 5, and 150 hp. A DC 15 Climb check is sufficient to climb a tree. Medium and dense forests have massive trees as well. These trees take up an entire square and provide cover to anyone behind them. They have AC 3, hardness 5, and 600 hp. Like their smaller counterparts, it takes a DC 15 Climb check to climb them.

Undergrowth: Vines, roots, and short bushes cover much of the ground in a forest. A space covered with light undergrowth costs 2 squares of movement to move into, and provides concealment. Undergrowth increases the DC of Acrobatics and Stealth checks by 2 because the leaves and branches get in the way. Heavy undergrowth costs 4 squares of movement to move into and provides concealment with a 30% miss chance (instead of the usual 20%). It increases the DC of Acrobatics checks by 5. Heavy undergrowth is easy to hide in, granting a +5 circumstance bonus on Stealth checks. Running and charging are impossible. Squares with undergrowth are often clustered together. Undergrowth and trees aren’t mutually exclusive; it’s common for a 5-foot square to have both a tree and undergrowth.

Forest Canopy: It’s common for elves and other forest dwellers to live on raised platforms far above the surface floor. These wooden platforms often have rope bridges between them. To get to the treehouses, characters ascend the trees’ branches (Climb DC 15), use rope ladders (Climb DC 0), or take pulley elevators (which can be made to rise a number of feet equal to a Strength check, made each round as a full-round action). Creatures on platforms or branches in a forest canopy are considered to have cover when fighting creatures on the ground, and in medium or dense forests they have concealment as well.

Other Forest Terrain Elements: Fallen logs generally stand about 3 feet high and provide cover just as low walls do. They cost 5 feet of movement to cross. Forest streams average 5 to 10 feet wide and no more than 5 feet deep. Pathways wind through most forests, allowing normal movement and providing neither cover nor concealment. These paths are less common in dense forests, but even unexplored forests have occasional game trails.

Stealth and Detection in a Forest: In a sparse forest, the maximum distance at which a Perception check for detecting the nearby presence of others can succeed is 3d6 × 10 feet. In a medium forest, this distance is 2d8 × 10 feet, and in a dense forest it is 2d6 × 10 feet.

Because any square with undergrowth provides concealment, it’s usually easy for a creature to use the Stealth skill in the forest. Logs and massive trees provide cover, which also makes hiding possible.

The background noise in the forest makes Perception checks that rely on sound more difficult, increasing the DC of the check by 2 per 10 feet, not 1.

Marsh Terrain

Source PRPG Core Rulebook pg. 427
Two categories of marsh exist: relatively dry moors and watery swamps. Both are often bordered by lakes (described in Aquatic Terrain), which are effectively a third category of terrain found in marshes.
Marsh Category
MoorSwamp
Shallow bog20%40%
Deep bog5%20%
Light undergrowth30%20%
Heavy undergrowth10%20%

Bogs: If a square is part of a shallow bog, it has deep mud or standing water of about 1 foot in depth. It costs 2 squares of movement to move into a square with a shallow bog, and the DC of Acrobatics checks in such a square increases by 2.

A square that is part of a deep bog has roughly 4 feet of standing water. It costs Medium or larger creatures 4 squares of movement to move into a square with a deep bog, or characters can swim if they wish. Small or smaller creatures must swim to move through a deep bog. Tumbling is impossible in a deep bog.

The water in a deep bog provides cover for Medium or larger creatures. Smaller creatures gain improved cover (+8 bonus to AC, +4 bonus on Reflex saves). Medium or larger creatures can crouch as a move action to gain this improved cover. Creatures with this improved cover take a –10 penalty on attacks against creatures that aren’t underwater.

Deep bog squares are usually clustered together and surrounded by an irregular ring of shallow bog squares. Both shallow and deep bogs increase the DC of Stealth checks by 2.

Undergrowth: The bushes, rushes, and other tall grasses in marshes function as undergrowth does in a forest. A square that is part of a bog does not also have undergrowth.

Quicksand: Patches of quicksand present a deceptively solid appearance (appearing as undergrowth or open land) that might trap careless characters. A character approaching a patch of quicksand at a normal pace is entitled to a DC 15 Survival check to spot the danger before stepping in, but charging or running characters don’t have a chance to detect a hidden patch before blundering into it. A typical patch of quicksand is 20 feet in diameter; the momentum of a charging or running character carries him 1d2 × 5 feet into the quicksand.

Effects of Quicksand: Characters in quicksand must make a DC 10 Swim check every round to simply tread water in place, or a DC 15 Swim check to move 5 feet in whatever direction is desired. If a trapped character fails this check by 5 or more, he sinks below the surface and begins to drown whenever he can no longer hold his breath (see the Swim skill description in Chapter 4).

Characters below the surface of quicksand may swim back to the surface with a successful Swim check (DC 15, +1 per consecutive round of being under the surface).

Rescue: Pulling out a character trapped in quicksand can be difficult. A rescuer needs a branch, spear haft, rope, or similar tool that enables him to reach the victim with one end of it. Then he must make a DC 15 Strength check to successfully pull the victim, and the victim must make a DC 10 Strength check to hold onto the branch, pole, or rope. If both checks succeed, the victim is pulled 5 feet closer to safety. If the victim fails to hold on, he must make a DC 15 Swim check immediately to stay above the surface.

Hedgerows: Common in moors, hedgerows are tangles of stones, soil, and thorny bushes. Narrow hedgerows function as low walls, and it takes 3 squares of movement to cross them. Wide hedgerows are more than 5 feet tall and take up entire squares. They provide total cover, just as a wall does. It takes 4 squares of movement to move through a square with a wide hedgerow; creatures that succeed on a DC 10 Climb check need only 2 squares of movement to move through the square.

Other Marsh Terrain Elements: Some marshes, particularly swamps, have trees just as forests do, usually clustered in small stands. Paths lead across many marshes, winding to avoid bog areas. As in forests, paths allow normal movement and don’t provide the concealment that undergrowth does.

Stealth and Detection in a Marsh: In a marsh, the maximum distance at which a Perception check for detecting the nearby presence of others can succeed is 6d6 × 10 feet. In a swamp, this distance is 2d8 × 10 feet. Undergrowth and deep bogs provide plentiful concealment, so it’s easy to use Stealth in a marsh.

Hills Terrain

Source PRPG Core Rulebook pg. 427
A hill can exist in most other types of terrain, but hills can also dominate the landscape. Hills terrain is divided into two categories: gentle hills and rugged hills. Hills terrain often serves as a transition zone between rugged terrain such as mountains and flat terrain such as plains.
Hills Category
Gentle HillsRugged Hills
Gradual slope75%40%
Steep slope20%50%
Cliff5%10%
Light undergrowth15%15%

Gradual Slope: This incline isn’t steep enough to affect movement, but characters gain a +1 bonus on melee attacks against foes downhill from them.

Steep Slope: Characters moving uphill (to an adjacent square of higher elevation) must spend 2 squares of movement to enter each square of steep slope. Characters running or charging downhill (moving to an adjacent square of lower elevation) must succeed on a DC 10 Acrobatics check upon entering the first steep slope square. Mounted characters make a DC 10 Ride check instead. Characters who fail this check stumble and must end their movement 1d2 × 5 feet later. Characters who fail by 5 or more fall prone in the square where they end their movement. A steep slope increases the DC of Acrobatics checks by 2.

Cliff: A cliff typically requires a DC 15 Climb check to scale and is 1d4 × 10 feet tall, although the needs of your map might mandate a taller cliff. A cliff isn’t perfectly vertical, taking up 5-foot squares if it’s less than 30 feet tall and 10-foot squares if it’s 30 feet or taller.

Light Undergrowth: Sagebrush and other scrubby bushes grow on hills, although they rarely cover the landscape. Light undergrowth provides concealment and increases the DC of Acrobatics and Stealth checks by 2.

Other Hills Terrain Elements: Trees aren’t out of place in hills terrain, and valleys often have active streams (5 to 10 feet wide and no more than 5 feet deep) or dry streambeds (treat as a trench 5 to 10 feet across) in them. If you add a stream or streambed, remember that water always flows downhill.

Stealth and Detection in Hills: In gentle hills, the maximum distance at which a Perception check for detecting the nearby presence of others can succeed is 2d10 × 10 feet. In rugged hills, this distance is 2d6 × 10 feet. Hiding in hills terrain can be difficult if there isn’t undergrowth around. A hilltop or ridge provides enough cover to hide from anyone below the hilltop or ridge.

Mountain Terrain

Source PRPG Core Rulebook pg. 428
The three mountain terrain categories are alpine meadows, rugged mountains, and forbidding mountains. As characters ascend into a mountainous area, they’re likely to face each terrain category in turn, beginning with alpine meadows, extending through rugged mountains, and reaching forbidding mountains near the summit.

Mountains have an important terrain element, the rock wall, that is marked on the border between squares rather than taking up squares itself.
Mountain Category
Alpine MeadowRuggedForbidding
Gradual slope50%25%15%
Steep slope40%55%55%
Cliff10%15%20%
Chasm5%10%
Light undergrowth20%10%
Scree20%30%
Dense Rubble20%30%

Gradual and Steep Slopes: These function as described in Hills Terrain.

Cliff: These terrain elements also function like their hills terrain counterparts, but they’re typically 2d6 × 10 feet tall. Cliffs taller than 80 feet take up 20 feet of horizontal space.

Chasm: Usually formed by natural geological processes, chasms function like pits in a dungeon setting. Chasms aren’t hidden, so characters won’t fall into them by accident (although bull rushes are another story). A typical chasm is 2d4 × 10 feet deep, at least 20 feet long, and anywhere from 5 feet to 20 feet wide. It takes a DC 15 Climb check to climb out of a chasm. In forbidding mountain terrain, chasms are typically 2d8 × 10 feet deep.

Light Undergrowth: This functions as described in Forest Terrain.

Scree: A field of shifting gravel, scree doesn’t affect speed, but it can be treacherous on a slope. The DC of Acrobatics checks increases by 2 if there’s scree on a gradual slope and by 5 if there’s scree on a steep slope. The DC of Stealth checks increases by 2 if the scree is on a slope of any kind.

Dense Rubble: The ground is covered with rocks of all sizes. It costs 2 squares of movement to enter a square with dense rubble. The DC of Acrobatics checks on dense rubble increases by 5, and the DC of Stealth checks increases by 2.

Rock Wall: A vertical plane of stone, rock walls require DC 25 Climb checks to ascend. A typical rock wall is 2d4 × 10 feet tall in rugged mountains and 2d8 × 10 feet tall in forbidding mountains. Rock walls are drawn on the edges of squares, not in the squares themselves.

Cave Entrance: Found in cliff and steep slope squares and next to rock walls, cave entrances are typically between 5 and 20 feet wide and 5 feet deep. A cave could be anything from a simple chamber to the entrance to an elaborate dungeon. Caves used as monster lairs typically have 1d3 rooms that are 1d4 × 10 feet across.

Other Mountain Terrain Features: Most alpine meadows begin above the treeline, so trees and other forest elements are rare in the mountains. Mountain terrain can include active streams (5 to 10 feet wide and no more than 5 feet deep) and dry streambeds (treat as a trench 5 to 10 feet across). Particularly high-altitude areas tend to be colder than the lowland areas that surround them, so they might be covered in ice sheets (described in Desert Terrain).

Stealth and Detection in Mountains: As a guideline, the maximum distance in mountain terrain at which a Perception check for detecting the nearby presence of others can succeed is 4d10 × 10 feet. Certain peaks and ridgelines afford much better vantage points, of course, and twisting valleys and canyons have much shorter spotting distances. Because there’s little vegetation to obstruct line of sight, the specifics on your map are your best guide for the range at which an encounter could begin. As in hills terrain, a ridge or peak provides enough cover to hide from anyone below the high point.

It’s easier to hear faraway sounds in the mountains. The DC of Perception checks that rely on sound increase by 1 per 20 feet between listener and source, not per 10 feet.

Desert Terrain

Source PRPG Core Rulebook pg. 430
Desert terrain exists in warm, temperate, and cold climates, but all deserts share one common trait: little rain. The three categories of desert terrain are tundra (cold desert), rocky deserts (often temperate), and sandy deserts (often warm).

Tundra differs from the other desert categories in two important ways. Because snow and ice cover much of the landscape, it’s easy to find water. During the height of summer, the permafrost thaws to a depth of a foot or so, turning the landscape into a vast field of mud. The muddy tundra affects movement and skill use as the shallow bogs described in Marsh Terrain, although there’s little standing water.

The table below describes terrain elements found in each of the three desert categories. The terrain elements on this table are mutually exclusive; for instance, a square of tundra might contain either light undergrowth or an ice sheet, but not both.
Desert Category
TundraRockySandy
Light undergrowth15%5%5%
Ice sheets25%
Light rubble5%30%10%
Dense rubble30%5%
Sand dunes50%

Light Undergrowth: Consisting of scrubby, hardy bushes and cacti, light undergrowth functions as described for other terrain types.

Ice Sheet: The ground is covered with slippery ice. It costs 2 squares of movement to enter a square covered by an ice sheet, and the DC of Acrobatics checks there increases by 5. A DC 10 Acrobatics check is required to run or charge across an ice sheet.

Light Rubble: Small rocks are strewn across the ground, making nimble movement more difficult. The DC of Acrobatics checks increases by 2.

Dense Rubble: This terrain feature consists of more and larger stones. It costs 2 squares of movement to enter a square with dense rubble. The DC of Acrobatics checks increases by 5, and the DC of Stealth checks increases by 2.

Sand Dunes: Created by the action of wind on sand, dunes function as hills that move. If the wind is strong and consistent, a sand dune can move several hundred feet in a week’s time. Sand dunes can cover hundreds of squares. They always have a gentle slope pointing in the direction of the prevailing wind and a steep slope on the leeward side.

Other Desert Terrain Features: Tundra is sometimes bordered by forests, and the occasional tree isn’t out of place in the cold wastes. Rocky deserts have towers and mesas consisting of flat ground surrounded on all sides by cliffs and steep slopes (as described in Mountain Terrain). Sandy deserts sometimes have quicksand; this functions as described in Marsh Terrain, although desert quicksand is a waterless mixture of fine sand and dust. All desert terrain is crisscrossed with dry streambeds (treat as trenches 5 to 15 feet wide) that fill with water on the rare occasions when rain falls.

Stealth and Detection in the Desert: In general, the maximum distance in desert terrain at which a Perception check for detecting the nearby presence of others can succeed is 6d6 × 20 feet; beyond this distance, elevation changes and heat distortion in warm deserts makes sight-based Perception impossible. The presence of dunes in sandy deserts limits spotting distance to 6d6 × 10 feet. The scarcity of undergrowth or other elements that offer concealment or cover makes using Stealth more difficult.

Plains Terrain

Source PRPG Core Rulebook pg. 431
Plains come in three categories: farms, grasslands, and battlefields. Farms are common in settled areas, while grasslands represent untamed plains. The battlefields where large armies clash are temporary places, usually reclaimed by natural vegetation or the farmer’s plow. Battlefields represent a third terrain category because adventurers tend to spend a lot of time there, not because they’re particularly prevalent.

The table below shows the proportions of terrain elements in the different categories of plains. On a farm, light undergrowth represents most mature grain crops, so farms growing vegetable crops will have less light undergrowth, as will all farms during the time between harvest and a few months after planting.

The terrain elements in the table below are mutually exclusive.
Plains Category
FarmGrasslandsBattlefield
Light undergrowth40%20%10%
Heavy undergrowth10%
Light rubble10%
Trench5%5%
Berm5%

Undergrowth: Whether they’re crops or natural vegetation, the tall grasses of the plains function like light undergrowth in a forest. Particularly thick bushes form patches of heavy undergrowth that dot the landscape in grasslands.

Light Rubble: On the battlefield, light rubble usually represents something that was destroyed: the ruins of a building or the scattered remnants of a stone wall, for example. It functions as described in the Desert Terrain section.

Trench: Often dug before a battle to protect soldiers, a trench functions as a low wall, except that it provides no cover against adjacent foes. It costs 2 squares of movement to leave a trench, but it costs nothing extra to enter one. Creatures outside a trench who make a melee attack against a creature inside the trench gain a +1 bonus on melee attacks because they have higher ground. In farm terrain, trenches are generally irrigation ditches.

Berm: A common defensive structure, a berm is a low, earthen wall that slows movement and provides a measure of cover. Put a berm on the map by drawing two adjacent rows of steep slope (described in Hills Terrain), with the edges of the berm on the downhill side. Thus, a character crossing a 2-square berm will travel uphill for 1 square, then downhill for 1 square. Two square berms provide cover as low walls for anyone standing behind them. Larger berms provide the low wall benefit for anyone standing 1 square downhill from the top of the berm.

Fences: Wooden fences are generally used to contain livestock or impede oncoming soldiers. It costs an extra square of movement to cross a wooden fence. A stone fence provides a measure of cover as well, functioning as low walls. Mounted characters can cross a fence without slowing their movement if they succeed on a DC 15 Ride check. If the check fails, the steed crosses the fence, but the rider falls out of the saddle.

Other Plains Terrain Features: Occasional trees dot the landscape in many plains, although on battlefields they’re often felled to provide raw material for siege engines (described in Urban Features). Hedgerows (described in Marsh Terrain) are found in plains as well. Streams, generally 5 to 20 feet wide and 5 to 10 feet deep, are commonplace.

Stealth and Detection in Plains: In plains terrain, the maximum distance at which a Perception check for detecting the nearby presence of others can succeed is 6d6 × 40 feet, although the specifics of your map might restrict line of sight. Cover and concealment are not uncommon, so a good place of refuge is often nearby, if not right at hand.

Aquatic Terrain

Source PRPG Core Rulebook pg. 432
Aquatic terrain is the least hospitable to most PCs, because they can’t breathe there. Aquatic terrain doesn’t offer the variety that land terrain does. The ocean floor holds many marvels, including undersea analogues of any of the terrain elements described earlier in this section, but if characters find themselves in the water because they were bull rushed off the deck of a pirate ship, the tall kelp beds hundreds of feet below them don’t matter. Accordingly, these rules simply divide aquatic terrain into two categories: flowing water (such as streams and rivers) and non-flowing water (such as lakes and oceans).

Flowing Water: Large, placid rivers move at only a few miles per hour, so they function as still water for most purposes. But some rivers and streams are swifter; anything floating in them moves downstream at a speed of 10 to 40 feet per round. The fastest rapids send swimmers bobbing downstream at 60 to 90 feet per round. Fast rivers are always at least rough water (Swim DC 15), and whitewater rapids are stormy water (Swim DC 20). If a character is in moving water, move her downstream the indicated distance at the end of her turn. A character trying to maintain her position relative to the riverbank can spend some or all of her turn swimming upstream.

Swept Away: Characters swept away by a river moving 60 feet per round or faster must make DC 20 Swim checks every round to avoid going under. If a character gets a check result of 5 or more over the minimum necessary, she arrests her motion by catching a rock, tree limb, or bottom snag—she is no longer being carried along by the flow of the water. Escaping the rapids by reaching the bank requires three DC 20 Swim checks in a row. Characters arrested by a rock, limb, or snag can’t escape under their own power unless they strike out into the water and attempt to swim their way clear. Other characters can rescue them as if they were trapped in quicksand (described in Marsh Terrain).

Non-Flowing Water: Lakes and oceans simply require a swim speed or successful Swim checks to move through (DC 10 in calm water, DC 15 in rough water, DC 20 in stormy water). Characters need a way to breathe if they’re underwater; failing that, they risk drowning. When underwater, characters can move in any direction.

Stealth and Detection Underwater: How far you can see underwater depends on the water’s clarity. As a guideline, creatures can see 4d8 × 10 feet if the water is clear, and 1d8 × 10 feet if it’s murky. Moving water is always murky, unless it’s in a particularly large, slow-moving river.

It’s hard to find cover or concealment to hide underwater (except along the sea floor).

Invisibility: An invisible creature displaces water and leaves a visible, body-shaped “bubble” where the water was displaced. The creature still has concealment (20% miss chance), but not total concealment (50% miss chance).