Environmental Effects

Lesson 93 explored:

CURSES

and:

MAGICAL CONTAGIONS

Now the Gameplay Toolbox turns something much more ordinary into a genuine threat:

THE ENVIRONMENT

A monster doesn't need to attack you for an adventure to become dangerous.

Sometimes the enemy is:

THE OCEAN

THE COLD

THE HEAT

A BLIZZARD

THE THIN AIR OF A MOUNTAIN

A FROZEN LAKE

or:

A VIOLENT WIND

The SRD 5.2.1 provides nine specific Environmental Effects that a Game Master can use:

DEEP WATER

EXTREME COLD

EXTREME HEAT

FRIGID WATER

HEAVY PRECIPITATION

HIGH ALTITUDE

SLIPPERY ICE

STRONG WIND

and:

THIN ICE

These rules connect directly to concepts you already know, especially:

SAVING THROWS

EXHAUSTION

DIFFICULT TERRAIN

PRONE

PERCEPTION

FLYING

and:

TRAVEL

 

PART ONE: THE CORE IDEA

Environmental Effects give the GM:

READY MADE RULES FOR HOSTILE ENVIRONMENTS

Instead of improvising a random penalty every time the characters enter a dangerous place, the GM can use the procedure already established by the SRD.

For example:

A character swims hundreds of feet below the surface.

Use:

DEEP WATER

A party crosses an arctic wasteland.

Use:

EXTREME COLD

A hero falls through a frozen lake.

Use:

FRIGID WATER

A flying character attempts to remain airborne during a violent gale.

Use:

STRONG WIND

The important principle is:

IDENTIFY THE ENVIRONMENTAL EFFECT

then:

APPLY ITS SPECIFIC RULE

Do not assume that every harsh environment deals damage.

Many of these effects instead produce:

EXHAUSTION

DISADVANTAGE

DIFFICULT TERRAIN

PRONE

or:

CHANGES TO TRAVEL

PART TWO: ENVIRONMENTAL EFFECTS AT A GLANCE

The nine effects can be grouped by the kind of danger they create.

EXHAUSTION THREATS

DEEP WATER

EXTREME COLD

EXTREME HEAT

FRIGID WATER

VISIBILITY AND COMBAT THREATS

HEAVY PRECIPITATION

STRONG WIND

TRAVEL THREAT

HIGH ALTITUDE

TERRAIN THREATS

SLIPPERY ICE

THIN ICE

Several can occur:

IN THE SAME ENVIRONMENT

A frozen mountain expedition might involve:

EXTREME COLD

HIGH ALTITUDE

STRONG WIND

SLIPPERY ICE

and:

THIN ICE

The SRD does not state that choosing one environmental effect automatically prevents another from applying.

When several descriptions genuinely fit the situation, the GM can adjudicate them using their specific rules.

PART THREE: DEEP WATER

Deep Water means water that is:

MORE THAN 100 FEET DEEP

The danger comes from:

PRESSURE

and:

COLD TEMPERATURE

 

The rule applies while:

SWIMMING THROUGH DEEP WATER

THE CHECK

After:

EACH HOUR OF SWIMMING IN DEEP WATER

a creature that lacks:

A SWIM SPEED

must make:

DC 10 CONSTITUTION SAVING THROW

Success

No Exhaustion from that check.

Failure

Gain:

1 EXHAUSTION LEVEL

IMPORTANT EXCEPTION

If the creature has:

A SWIM SPEED

the Deep Water rule does not require this saving throw.

That is a significant advantage for creatures naturally or magically adapted to aquatic movement.

EXAMPLE

A Human adventurer has:

Speed:

30 FEET

Swim Speed:

NONE

The character spends:

3 HOURS

swimming through water more than 100 feet deep.

At the end of Hour 1:

DC 10 CONSTITUTION SAVE

At the end of Hour 2:

DC 10 CONSTITUTION SAVE

At the end of Hour 3:

DC 10 CONSTITUTION SAVE

Suppose the results are:

Hour 1:

SUCCESS

Hour 2:

FAILURE

Hour 3:

FAILURE

The character gains:

2 EXHAUSTION LEVELS

WHY THIS IS DANGEROUS

From the Exhaustion rules you already learned, every Exhaustion level imposes:

MINUS 2 TO D20 TESTS

and:

MINUS 5 FEET TO SPEED

At:

EXHAUSTION 6

the creature:

DIES

So Deep Water is not merely:

SLOW SWIMMING

Remaining submerged for long periods can become:

LETHAL

DEEP WATER DOES NOT DIRECTLY DEAL DAMAGE

The Environmental Effect says:

FAILED SAVE EQUALS EXHAUSTION

It does not say:

TAKE COLD DAMAGE

or:

TAKE BLUDGEONING DAMAGE FROM PRESSURE

Do not invent extra damage merely because the description mentions:

PRESSURE

and:

COLD

Those words explain the environmental danger.

The mechanical effect is:

THE CONSTITUTION SAVE AND EXHAUSTION

PART FOUR: DEEP WATER AND SWIMMING

Remember the normal Swimming rule.

A creature without a Swim Speed normally spends:

1 EXTRA FOOT OF MOVEMENT

for every foot it swims.

That is a separate movement rule.

Deep Water adds:

THE HOURLY CONSTITUTION SAVE

So an adventurer without a Swim Speed can experience both:

SLOWER SWIMMING

and:

DEEP WATER EXHAUSTION RISK

A creature with a Swim Speed avoids the normal extra Swimming movement cost and also avoids the saving throw from:

THIS DEEP WATER RULE

PART FIVE: DEEP WATER AND FRIGID WATER ARE DIFFERENT

This distinction is important.

DEEP WATER

asks:

HOW DEEP IS THE WATER?

Threshold:

MORE THAN 100 FEET

Timing:

EACH HOUR

Relevant adaptation:

SWIM SPEED

FRIGID WATER

asks:

HOW COLD IS THE WATER?

Timing:

MINUTES

Relevant adaptations include:

COLD RESISTANCE

COLD IMMUNITY

and:

NATURAL ADAPTATION TO ICE COLD WATER

So:

DEEP WATER

and:

FRIGID WATER

are not two names for the same rule.

PART SIX: EXTREME COLD

Extreme Cold begins when the temperature is:

0 DEGREES FAHRENHEIT OR LOWER

 

A creature exposed to this cold makes:

DC 10 CONSTITUTION SAVING THROW

at:

THE END OF EACH HOUR

Success

No Exhaustion from that check.

Failure

Gain:

1 EXHAUSTION LEVEL

EXAMPLE

A party spends:

5 HOURS

crossing a frozen plain at a temperature below the threshold.

Each exposed creature normally makes:

5 DC 10 CONSTITUTION SAVING THROWS

one at the end of each hour.

A creature failing three of them gains:

EXHAUSTION 3

That means:

MINUS 6 TO D20 TESTS

and:

MINUS 15 FEET TO SPEED

for as long as those Exhaustion levels remain.

PART SEVEN: COLD RESISTANCE AND IMMUNITY

A creature with:

RESISTANCE TO COLD DAMAGE

or:

IMMUNITY TO COLD DAMAGE

automatically:

SUCCEEDS ON THE EXTREME COLD SAVE

 

No roll is required.

IMPORTANT

Resistance doesn't merely give:

ADVANTAGE

It produces:

AUTOMATIC SUCCESS

for this particular Environmental Effect.

Likewise, Immunity produces:

AUTOMATIC SUCCESS

EXAMPLE

Creature A:

No Cold Resistance.

Result:

DC 10 SAVE EACH HOUR

Creature B:

Cold Resistance.

Result:

AUTOMATIC SUCCESS EACH HOUR

Creature C:

Cold Immunity.

Result:

AUTOMATIC SUCCESS EACH HOUR

PART EIGHT: DO NOT IMPORT AN UNLISTED COLD EXCEPTION

The SRD 5.2.1 Environmental Effect explicitly names:

COLD RESISTANCE

and:

COLD IMMUNITY

as automatic success conditions.

This subsection does not state that ordinary cold weather clothing automatically produces the same result.

If another rule specifically modifies the situation:

APPLY THAT RULE

But do not silently import an exception from:

AN OLDER RULESET

or:

ANOTHER SOURCE

PART NINE: EXTREME HEAT

Extreme Heat begins when the temperature is:

100 DEGREES FAHRENHEIT OR HIGHER

But there is another important requirement.

The creature must be:

EXPOSED TO THE EXTREME HEAT

and:

WITHOUT ACCESS TO DRINKABLE WATER

 

Only then does this Environmental Effect require its Constitution saves.

THE SAVE

At the end of:

EACH HOUR

make:

CONSTITUTION SAVING THROW

The DC starts much lower than Extreme Cold but:

INCREASES OVER TIME

FIRST HOUR

DC 5

SECOND HOUR

DC 6

THIRD HOUR

DC 7

FOURTH HOUR

DC 8

FIFTH HOUR

DC 9

and so on.

The formula is:

DC 5 FOR THE FIRST HOUR

then:

PLUS 1 FOR EACH ADDITIONAL HOUR

FAILURE

Gain:

1 EXHAUSTION LEVEL

PART TEN: DRINKABLE WATER MATTERS

The Extreme Heat rule applies to a creature:

WITHOUT ACCESS TO DRINKABLE WATER

That phrase is mechanically important.

If the creature has access to:

DRINKABLE WATER

this particular Environmental Effect does not instruct the creature to make the hourly heat save.

Do not ignore:

WATER

when applying this rule.

This makes preparation meaningful.

A desert expedition isn't only about:

TEMPERATURE

It can also become a problem of:

WATER SUPPLY

PART ELEVEN: ARMOR IN EXTREME HEAT

A creature wearing:

MEDIUM ARMOR

or:

HEAVY ARMOR

has:

DISADVANTAGE

on the Extreme Heat Constitution Saving Throw.

 

EXAMPLE

A Paladin in Heavy Armor reaches the end of the third hour without access to drinkable water.

Save DC:

7

Normally:

ROLL 1D20

But Heavy Armor causes:

DISADVANTAGE

So:

ROLL TWO D20s

and use:

THE LOWER RESULT

then apply the Constitution Saving Throw modifiers.

LIGHT ARMOR

The rule does not impose this special Disadvantage on:

LIGHT ARMOR

NO ARMOR

Likewise, a creature wearing no armor doesn't receive this armor based Disadvantage.

PART TWELVE: FIRE RESISTANCE AND IMMUNITY

A creature with:

RESISTANCE TO FIRE DAMAGE

or:

IMMUNITY TO FIRE DAMAGE

automatically succeeds on:

THE EXTREME HEAT SAVING THROW

 

Again:

AUTOMATIC SUCCESS

not merely Advantage.

EXAMPLE

A creature wearing Heavy Armor has:

FIRE RESISTANCE

Heavy Armor would normally impose:

DISADVANTAGE

But Fire Resistance means the creature:

AUTOMATICALLY SUCCEEDS

There is no need to roll.

PART THIRTEEN: EXTREME COLD VS EXTREME HEAT

The mechanics are intentionally different.

EXTREME COLD

Threshold:

0 DEGREES FAHRENHEIT OR LOWER

Save:

DC 10 CONSTITUTION

Timing:

EACH HOUR

Failure:

1 EXHAUSTION

Automatic success:

COLD RESISTANCE OR IMMUNITY

EXTREME HEAT

Threshold:

100 DEGREES FAHRENHEIT OR HIGHER

Requires:

NO ACCESS TO DRINKABLE WATER

Save:

CONSTITUTION

First hour:

DC 5

Then:

PLUS 1 DC PER ADDITIONAL HOUR

Medium or Heavy Armor:

DISADVANTAGE

Automatic success:

FIRE RESISTANCE OR IMMUNITY

The two effects should not be run as:

THE SAME RULE WITH DIFFERENT FLAVOR

PART FOURTEEN: FRIGID WATER

Frigid Water uses:

MINUTES

rather than hours.

A creature can remain immersed without ill effects for a number of minutes equal to:

ITS CONSTITUTION SCORE

 

Notice:

CONSTITUTION SCORE

not:

CONSTITUTION MODIFIER

This distinction is extremely important.

EXAMPLE

Constitution:

16

Constitution modifier:

PLUS 3

Safe immersion time:

16 MINUTES

Not:

3 MINUTES

PART FIFTEEN: AFTER THE SAFE PERIOD

Once the creature has remained immersed for its Constitution score in minutes, every:

ADDITIONAL MINUTE

requires:

DC 10 CONSTITUTION SAVING THROW

Failure:

GAIN 1 EXHAUSTION LEVEL

 

EXAMPLE

Constitution:

14

First:

14 MINUTES

No ill effects from this rule.

Minute 15:

DC 10 CONSTITUTION SAVE

Minute 16:

DC 10

Minute 17:

DC 10

and so on.

Suppose the character fails Minute 15 and Minute 17.

Result:

EXHAUSTION 2

That is a rapid escalation.

Frigid Water is therefore much more immediately dangerous than:

EXTREME COLD AIR

because its checks can begin occurring:

EVERY MINUTE

PART SIXTEEN: WHO AUTOMATICALLY SUCCEEDS IN FRIGID WATER?

Three groups automatically succeed on the Frigid Water save:

CREATURES WITH COLD RESISTANCE

CREATURES WITH COLD IMMUNITY

and:

CREATURES NATURALLY ADAPTED TO LIVING IN ICE COLD WATER

 

The third category is unique to:

FRIGID WATER

Extreme Cold does not use that exact additional wording in its own entry.

PART SEVENTEEN: A SWIM SPEED DOES NOT AUTOMATICALLY PROTECT AGAINST FRIGID WATER

This is a very important distinction.

Deep Water says a creature with:

A SWIM SPEED

doesn't make its Deep Water save.

Frigid Water does not list Swim Speed as an automatic success condition.

It lists:

COLD RESISTANCE

COLD IMMUNITY

or:

NATURAL ADAPTATION TO ICE COLD WATER

So a creature might be an excellent swimmer while still being vulnerable to:

EXTREME COLD WATER

Do not merge:

SWIMMING ABILITY

with:

COLD ADAPTATION

unless a specific rule connects them.

PART EIGHTEEN: HEAVY PRECIPITATION

Heavy Precipitation includes:

HEAVY RAIN

and:

HEAVY SNOWFALL

 

Everything inside the affected area becomes:

LIGHTLY OBSCURED

Creatures in the area also have:

DISADVANTAGE ON ALL WISDOM PERCEPTION CHECKS

WHAT LIGHTLY OBSCURED MEANS

From the Rules Glossary:

A creature has Disadvantage on Wisdom Perception checks made to:

SEE SOMETHING

in a Lightly Obscured area.

Heavy Precipitation goes further by explicitly saying creatures in the area have Disadvantage on:

ALL WISDOM PERCEPTION CHECKS

So the weather can interfere with perception beyond purely:

VISUAL DETAILS

according to the Environmental Effect's own wording.

ADVANTAGE AND DISADVANTAGE DO NOT STACK

If Lightly Obscured and Heavy Precipitation both produce Disadvantage on the same relevant check:

YOU STILL ROLL ONLY TWO D20s

Multiple sources of Disadvantage:

DO NOT STACK

PART NINETEEN: HEAVY RAIN AND OPEN FLAMES

Heavy rain also:

EXTINGUISHES OPEN FLAMES

 

Examples of open flames can include things such as:

TORCHES

CAMPFIRES

or another exposed flame when appropriate.

The exact object or effect can have its own specific rule.

IMPORTANT

The rule specifically states:

HEAVY RAIN

extinguishes open flames.

It does not say in this entry that:

HEAVY SNOWFALL

automatically does the same.

Read the wording precisely.

PART TWENTY: HEAVY PRECIPITATION IN COMBAT

Imagine a battle during:

TORRENTIAL RAIN

The environmental consequences include:

LIGHTLY OBSCURED AREA

DISADVANTAGE ON WISDOM PERCEPTION CHECKS

and:

OPEN FLAMES EXTINGUISHED

But the entry does not say:

ALL ATTACK ROLLS HAVE DISADVANTAGE

It also doesn't say:

MOVEMENT IS DIFFICULT TERRAIN

unless another environmental or terrain rule makes it so.

This distinction prevents the GM from turning:

ONE WEATHER RULE

into:

FIVE UNWRITTEN PENALTIES

PART TWENTY ONE: HIGH ALTITUDE

High Altitude begins at:

10,000 FEET OR HIGHER ABOVE SEA LEVEL

 

The danger is the reduced amount of:

OXYGEN

But unlike Extreme Cold or Extreme Heat, High Altitude does not directly call for:

AN HOURLY CONSTITUTION SAVE

Instead it changes:

HOW TRAVEL TIME IS COUNTED

THE RULE

Each hour a creature spends:

TRAVELING AT HIGH ALTITUDE

counts as:

2 HOURS

for determining:

HOW LONG THAT CREATURE CAN TRAVEL

This connects directly to:

LESSON 91

and the Travel Pace rules.

PART TWENTY TWO: HIGH ALTITUDE AND THE EIGHT HOUR TRAVEL LIMIT

Normally characters can travel for:

8 HOURS

before Extended Travel begins creating Constitution Saving Throws.

At High Altitude, each actual hour of travel counts as:

2 HOURS

for that purpose.

So:

4 ACTUAL HOURS

count as:

8 HOURS OF TRAVEL

for determining how long the character has traveled.

The practical consequence is:

EXTENDED TRAVEL BECOMES RELEVANT MUCH SOONER

The High Altitude entry itself doesn't deal damage or directly grant Exhaustion.

Instead, it accelerates the travel clock that can eventually lead to:

EXTENDED TRAVEL SAVES

and therefore potentially:

EXHAUSTION

PART TWENTY THREE: HIGH ALTITUDE DOES NOT DOUBLE YOUR DISTANCE

This is a common conceptual mistake.

If one hour at High Altitude counts as:

TWO HOURS

that does not mean you travel:

TWICE AS FAR

The rule is modeling:

PHYSICAL STRAIN

not speed.

One actual hour still represents:

ONE ACTUAL HOUR OF MOVEMENT

It merely consumes:

TWO HOURS OF YOUR TRAVEL ENDURANCE

for the Travel Pace system.

PART TWENTY FOUR: ACCLIMATION

A creature can become:

ACCLIMATED

to High Altitude by spending:

30 DAYS OR MORE

at that elevation.

 

This establishes a meaningful long term distinction between:

NEW ARRIVALS

and:

CREATURES ACCUSTOMED TO HIGH ALTITUDE

The subsection does not provide:

AN ACCLIMATION CHECK

You don't roll every day.

The stated requirement is:

SPEND 30 DAYS OR MORE AT THE ELEVATION

ABOVE 20,000 FEET

Creatures cannot become acclimated to elevations above:

20,000 FEET

unless they are:

NATIVE TO SUCH ENVIRONMENTS

That creates an upper limit for ordinary acclimation.

IMPORTANT

Do not invent an additional:

CONSTITUTION SAVE

EXHAUSTION RATE

or:

DAMAGE ROLL

for High Altitude beyond what the SRD establishes.

The rule's explicit mechanic is:

TRAVEL HOURS COUNT DOUBLE

with the acclimation rules stated in the same entry.

PART TWENTY FIVE: SLIPPERY ICE

Slippery Ice creates two separate problems.

First:

IT IS DIFFICULT TERRAIN

Second:

IT CAN KNOCK YOU PRONE

 

DIFFICULT TERRAIN

Every foot moved through Difficult Terrain costs:

1 EXTRA FOOT OF MOVEMENT

So:

1 FOOT TRAVELED COSTS 2 FEET OF MOVEMENT

EXAMPLE

Speed:

30 FEET

If all movement occurs across Slippery Ice:

30 divided by 2 equals:

15 FEET OF ACTUAL TRAVEL

PART TWENTY SIX: THE SLIPPERY ICE SAVE

A creature must make:

DC 10 DEXTERITY SAVING THROW

when either of two things happens.

TRIGGER 1

It moves onto Slippery Ice for:

THE FIRST TIME ON A TURN

TRIGGER 2

It:

STARTS ITS TURN THERE

Failure:

PRONE

 

EXAMPLE

A Fighter begins a turn on normal stone.

The Fighter steps onto Slippery Ice.

Trigger:

DC 10 DEXTERITY SAVE

Failure:

PRONE

The Fighter is now lying on:

DIFFICULT TERRAIN

That can make recovering and repositioning much more costly.

PART TWENTY SEVEN: STARTING A TURN ON THE ICE

Suppose the Fighter survives the turn and is still standing on Slippery Ice when the next turn begins.

Immediately:

DC 10 DEXTERITY SAVE

because the Fighter:

STARTED THE TURN THERE

The hazard therefore remains relevant:

EVERY TURN YOU REMAIN ON IT

not merely when you first discover the ice.

PART TWENTY EIGHT: PRONE ON SLIPPERY ICE

Prone means:

YOUR ATTACK ROLLS HAVE DISADVANTAGE

Attacks against you have:

ADVANTAGE

if the attacker is within:

5 FEET

and:

DISADVANTAGE

if farther away.

To stand:

SPEND MOVEMENT EQUAL TO HALF YOUR SPEED

rounded down.

So Slippery Ice can create an unpleasant movement combination:

DIFFICULT TERRAIN

plus:

MOVEMENT SPENT TO STAND

PART TWENTY NINE: STRONG WIND

Strong Wind affects:

WEAPON ATTACKS

OPEN FLAMES

FOG

and:

FLYING CREATURES

It can also create:

SANDSTORMS

in deserts.

 

PART THIRTY: RANGED WEAPON ATTACKS

Strong Wind imposes:

DISADVANTAGE

on:

RANGED ATTACK ROLLS WITH WEAPONS

The wording is specific.

EXAMPLES

Longbow attack:

DISADVANTAGE

Shortbow attack:

DISADVANTAGE

Crossbow attack:

DISADVANTAGE

Thrown weapon used for a ranged weapon attack:

Apply the rule when it is a:

RANGED ATTACK ROLL WITH A WEAPON

IMPORTANT: SPELL ATTACKS

Strong Wind does not say:

ALL RANGED ATTACK ROLLS

It specifically says ranged attack rolls:

WITH WEAPONS

Therefore this Environmental Effect does not by itself impose Disadvantage on:

A RANGED SPELL ATTACK

unless another rule also applies.

This is exactly why precise terminology matters.

PART THIRTY ONE: OPEN FLAMES AND FOG

Strong Wind:

EXTINGUISHES OPEN FLAMES

and:

DISPERSES FOG

 

That can drastically change an encounter.

A party relying on:

TORCHLIGHT

might suddenly lose its light source.

Fog that previously provided concealment might:

DISAPPEAR

PART THIRTY TWO: FLYING IN STRONG WIND

A flying creature in Strong Wind must:

LAND AT THE END OF ITS TURN

or:

FALL

 

This is one of the most important environmental combat rules in the section.

EXAMPLE

A creature begins its turn:

40 FEET IN THE AIR

Strong Wind is active.

During its turn it can move toward:

SAFE GROUND

But at the end of the turn, if it has not:

LANDED

it:

FALLS

The normal Falling rules then become relevant.

FALL DAMAGE

Normally:

1D6 BLUDGEONING DAMAGE PER 10 FEET FALLEN

maximum:

20D6

and a creature taking fall damage normally lands:

PRONE

So Strong Wind can transform aerial combat into:

A SERIOUS POSITIONING PROBLEM

PART THIRTY THREE: HOVER DOES NOT OVERRIDE STRONG WIND BY ITSELF

The Flying glossary rule says Hover prevents falling in certain circumstances such as when a creature becomes:

INCAPACITATED

PRONE

or:

HAS FLY SPEED 0

But Strong Wind has its own specific rule:

LAND AT END OF TURN OR FALL

The Strong Wind entry does not provide an exception for:

HOVER

Therefore do not automatically invent one.

A feature would need to:

SPECIFICALLY OVERRIDE THE ENVIRONMENTAL EFFECT

for a different result.

PART THIRTY FOUR: DESERT SANDSTORMS

A Strong Wind in a desert can create:

A SANDSTORM

The sandstorm imposes:

DISADVANTAGE

on:

WISDOM PERCEPTION CHECKS

 

IMPORTANT

The rule says Strong Wind in a desert:

CAN CREATE

a sandstorm.

It does not say:

EVERY STRONG WIND IN A DESERT MUST ALWAYS CREATE ONE

The GM uses the environmental circumstances appropriately.

PART THIRTY FIVE: STRONG WIND DOES NOT AUTOMATICALLY CREATE DIFFICULT TERRAIN

The Strong Wind rule does not say:

MOVEMENT COSTS DOUBLE

It does not say:

SPEED IS HALVED

It does not say:

MELEE ATTACKS HAVE DISADVANTAGE

It gives:

SPECIFIC EFFECTS

Apply those effects.

Do not add unrelated penalties unless:

ANOTHER RULE

supports them.

PART THIRTY SIX: THIN ICE

Thin Ice is a weight based environmental hazard.

Each:

10 FOOT SQUARE AREA

has a weight tolerance equal to:

3D10 TIMES 10 POUNDS

 

EXAMPLE

GM rolls:

3D10

Results:

4

6

7

Total:

4 + 6 + 7 equals:

17

Multiply by:

10 POUNDS

Tolerance:

170 POUNDS

PART THIRTY SEVEN: WHEN DOES THE ICE BREAK?

The ice breaks when:

TOTAL WEIGHT ON THAT AREA

EXCEEDS ITS TOLERANCE

The word:

EXCEEDS

matters.

Tolerance:

170 POUNDS

Total weight:

170 POUNDS

Does it break from this rule?

NO

because the tolerance has not been exceeded.

Total weight:

171 POUNDS

Now:

YES

The tolerance has been exceeded.

PART THIRTY EIGHT: TOTAL WEIGHT MATTERS

The rule checks:

TOTAL WEIGHT

on that 10 foot square area.

So multiple creatures can combine their weight.

EXAMPLE

Ice tolerance:

300 POUNDS

Character A plus equipment:

160 POUNDS

Character B plus equipment:

150 POUNDS

Total:

160 + 150 equals:

310 POUNDS

310 is greater than 300.

Result:

ICE BREAKS

This makes spacing extremely important.

Several characters gathering on the same patch of Thin Ice can be far more dangerous than:

CROSSING ONE AT A TIME

PART THIRTY NINE: WHAT HAPPENS WHEN THIN ICE BREAKS?

When the ice breaks:

ALL CREATURES ON THE BROKEN ICE FALL THROUGH

Below the ice is:

FRIGID WATER

 

That means Thin Ice immediately connects to another Environmental Effect.

The danger is not:

JUST FALLING THROUGH

Now the characters may face:

FRIGID WATER

and its potentially rapid:

EXHAUSTION SAVES

PART FORTY: THIN ICE TO FRIGID WATER EXAMPLE

A Fighter has:

CONSTITUTION 15

The Fighter falls through Thin Ice.

The water below is Frigid Water.

The Fighter can remain immersed for:

15 MINUTES

without ill effects from the Frigid Water rule.

Beginning with:

MINUTE 16

each additional minute requires:

DC 10 CONSTITUTION SAVE

Failure:

1 EXHAUSTION LEVEL

Notice that the rule uses:

CONSTITUTION SCORE 15

not:

CONSTITUTION MODIFIER

PART FORTY ONE: ENVIRONMENTAL EFFECTS CAN CREATE CHAINS

One of the most useful GM lessons in this section is that an environment can produce:

A CHAIN OF EXISTING RULES

You do not need to invent a complicated new hazard.

Consider:

THIN ICE

Weight exceeds tolerance.

Then:

ICE BREAKS

Characters fall into:

FRIGID WATER

They eventually begin making:

CONSTITUTION SAVES

Failures cause:

EXHAUSTION

Exhaustion reduces:

D20 TESTS

and:

SPEED

A rescue attempt therefore becomes harder as:

EXHAUSTION INCREASES

That is a complete dramatic sequence created almost entirely by:

CONNECTING EXISTING SRD RULES

PART FORTY TWO: EXTREME COLD PLUS FRIGID WATER

A character in an icy wilderness might be exposed to:

EXTREME COLD

and then fall into:

FRIGID WATER

These are separate Environmental Effects with different timings.

Extreme Cold:

HOURLY

Frigid Water:

MINUTE BASED

If the GM determines that both descriptions apply to the situation, the SRD doesn't state that one automatically replaces the other.

The important point is to:

TRACK EACH SPECIFIC RULE CORRECTLY

rather than inventing one combined save with a new DC.

PART FORTY THREE: HIGH ALTITUDE PLUS EXTREME COLD

A mountain expedition might involve:

HIGH ALTITUDE

and:

EXTREME COLD

High Altitude affects:

TRAVEL ENDURANCE

Extreme Cold causes:

HOURLY CONSTITUTION SAVES

unless the creature automatically succeeds through Cold Resistance or Immunity.

These threats attack the party in:

DIFFERENT WAYS

High Altitude makes the day effectively longer for travel strain.

Extreme Cold can directly produce:

EXHAUSTION

The resulting Exhaustion can then reduce:

SPEED

which can affect:

TRAVEL

This is how environmental rules can interact naturally.

PART FORTY FOUR: HEAVY SNOW PLUS SLIPPERY ICE

A battlefield during a winter storm might include:

HEAVY SNOWFALL

and:

SLIPPERY ICE

Heavy Snowfall:

LIGHTLY OBSCURES THE AREA

and gives:

DISADVANTAGE ON WISDOM PERCEPTION CHECKS

Slippery Ice:

DIFFICULT TERRAIN

and potentially:

PRONE

Now the battlefield is difficult because of:

VISIBILITY

and:

MOVEMENT

without the GM inventing:

A RANDOM MINUS 4 TO EVERYTHING

PART FORTY FIVE: STRONG WIND PLUS HEAVY RAIN

A violent storm might contain:

STRONG WIND

and:

HEAVY RAIN

Heavy Rain:

LIGHTLY OBSCURED

DISADVANTAGE ON WISDOM PERCEPTION

EXTINGUISHES OPEN FLAMES

Strong Wind:

DISADVANTAGE ON RANGED WEAPON ATTACK ROLLS

EXTINGUISHES OPEN FLAMES

DISPERSES FOG

FLYERS MUST LAND OR FALL

The overlapping open flame effect doesn't become:

DOUBLE EXTINGUISHING

The same flame simply:

GOES OUT

Likewise, multiple sources of Disadvantage:

DO NOT STACK

PART FORTY SIX: THE ENVIRONMENT AND EXHAUSTION

Four Environmental Effects can directly produce:

EXHAUSTION

These are:

DEEP WATER

EXTREME COLD

EXTREME HEAT

and:

FRIGID WATER

This matters because Exhaustion is:

CUMULATIVE

Unlike most conditions, it has:

LEVELS

Each level produces:

MINUS 2 TO D20 TESTS

and:

MINUS 5 FEET TO SPEED

At Level 6:

DEATH

This means environmental danger can escalate gradually.

A character might begin a journey fully capable.

After repeated failures, that character can become:

SLOWER

WORSE AT ATTACKS

WORSE AT SAVES

WORSE AT ABILITY CHECKS

and eventually:

UNABLE TO SURVIVE

Environmental adventure design is therefore often about:

ACCUMULATING PRESSURE

rather than:

ONE HUGE DAMAGE ROLL

PART FORTY SEVEN: RESISTANCE CAN HAVE EFFECTS BEYOND HALVING DAMAGE

Earlier you learned:

RESISTANCE

normally halves damage of the matching type.

But these Environmental Effects demonstrate something important about:

SPECIFIC RULES

Cold Resistance normally means:

HALF COLD DAMAGE

Yet Extreme Cold and Frigid Water specifically say that Cold Resistance also causes:

AUTOMATIC SUCCESS ON THEIR SAVES

Fire Resistance normally means:

HALF FIRE DAMAGE

But Extreme Heat says Fire Resistance also grants:

AUTOMATIC SUCCESS ON ITS SAVE

These extra benefits exist because:

THE ENVIRONMENTAL EFFECTS SPECIFICALLY SAY SO

Do not assume every form of Resistance automatically protects against:

EVERY ENVIRONMENTAL PROBLEM

PART FORTY EIGHT: WHAT THE PLAYER ACTUALLY DOES

Environmental play should remain simple from the player's perspective.

The GM describes the danger.

For example:

“THE TEMPERATURE HAS FALLEN INTO EXTREME COLD.”

The player checks:

DO I HAVE COLD RESISTANCE OR IMMUNITY?

If no:

At the end of each exposed hour:

ROLL DC 10 CONSTITUTION SAVE

Failure:

GAIN 1 EXHAUSTION

Or the GM says:

“YOU HAVE FALLEN INTO FRIGID WATER.”

Player checks Constitution score:

14

The character has:

14 MINUTES

before the Frigid Water saves begin.

The rule tells the player exactly:

WHAT TO ROLL

WHEN TO ROLL

and:

WHAT FAILURE MEANS

PART FORTY NINE: WHAT THE GM ACTUALLY DOES

The GM can use a simple procedure.

STEP 1

Identify whether one of the nine Environmental Effects:

ACTUALLY APPLIES

STEP 2

Read the exact trigger.

Ask whether it occurs:

EACH HOUR

EACH MINUTE

ON ENTERING TERRAIN

AT START OF TURN

or:

AT END OF TURN

STEP 3

Check for specific exemptions.

Examples:

SWIM SPEED

COLD RESISTANCE

FIRE IMMUNITY

NATURAL COLD WATER ADAPTATION

STEP 4

Call for the exact save only when required.

STEP 5

Apply the exact consequence.

Examples:

EXHAUSTION

PRONE

DISADVANTAGE

FALLING

or:

TRAVEL TIME CHANGE

STEP 6

If the effect creates another rules situation, apply that next rule.

Example:

THIN ICE BREAKS

then:

FRIGID WATER

or:

STRONG WIND CAUSES A FLYER TO FALL

then:

FALLING HAZARD

This keeps environmental adjudication:

CONSISTENT

and:

PREDICTABLE

PART FIFTY: COMMON BEGINNER MISTAKES

MISTAKE 1: THINKING DEEP WATER STARTS AT 100 FEET

The rule says:

MORE THAN 100 FEET DEEP

MISTAKE 2: MAKING DEEP WATER SAVES EVERY MINUTE

Deep Water:

EACH HOUR

MISTAKE 3: MAKING A CREATURE WITH A SWIM SPEED ROLL THE DEEP WATER SAVE

The rule applies to a creature that:

LACKS A SWIM SPEED

MISTAKE 4: DEALING AUTOMATIC PRESSURE DAMAGE IN DEEP WATER

The Environmental Effect itself gives:

A CONSTITUTION SAVE AGAINST EXHAUSTION

It does not add automatic damage.

MISTAKE 5: USING EXTREME COLD ABOVE 0 DEGREES FAHRENHEIT

The listed threshold is:

0 OR LOWER

MISTAKE 6: MAKING EXTREME COLD SAVES EVERY MINUTE

They occur:

AT END OF EACH HOUR

MISTAKE 7: GIVING COLD RESISTANCE ADVANTAGE INSTEAD OF AUTOMATIC SUCCESS

The rule says:

AUTOMATIC SUCCESS

MISTAKE 8: IMPORTING AN UNLISTED AUTOMATIC COLD WEATHER CLOTHING EXCEPTION

Use:

THE SRD 5.2.1 RULE

and any other specific rule that genuinely applies.

MISTAKE 9: USING EXTREME HEAT BELOW 100 DEGREES FAHRENHEIT

Threshold:

100 OR HIGHER

MISTAKE 10: IGNORING ACCESS TO DRINKABLE WATER

Extreme Heat's save applies when the exposed creature is:

WITHOUT ACCESS TO DRINKABLE WATER

MISTAKE 11: USING DC 10 FOR EXTREME HEAT

First hour:

DC 5

Then:

PLUS 1 PER ADDITIONAL HOUR

MISTAKE 12: KEEPING THE EXTREME HEAT DC AT 5 FOREVER

It:

INCREASES EACH HOUR

MISTAKE 13: GIVING LIGHT ARMOR DISADVANTAGE ON THE EXTREME HEAT SAVE

The special Disadvantage applies to:

MEDIUM

and:

HEAVY ARMOR

MISTAKE 14: MAKING A FIRE RESISTANT CREATURE ROLL THE EXTREME HEAT SAVE

It:

AUTOMATICALLY SUCCEEDS

MISTAKE 15: USING CONSTITUTION MODIFIER FOR FRIGID WATER SAFE TIME

Use:

CONSTITUTION SCORE

MISTAKE 16: MAKING FRIGID WATER SAVES IMMEDIATELY

The creature first receives safe immersion time equal to:

CONSTITUTION SCORE IN MINUTES

MISTAKE 17: MAKING FRIGID WATER SAVES HOURLY

After the safe period:

EACH ADDITIONAL MINUTE

MISTAKE 18: ASSUMING A SWIM SPEED AUTOMATICALLY PROTECTS AGAINST FRIGID WATER

It does not appear among the listed automatic success conditions.

MISTAKE 19: FORGETTING NATURAL ICE COLD WATER ADAPTATION

Such creatures:

AUTOMATICALLY SUCCEED

on Frigid Water saves.

MISTAKE 20: THINKING HEAVY PRECIPITATION MAKES EVERYTHING HEAVILY OBSCURED

It makes the area:

LIGHTLY OBSCURED

MISTAKE 21: GIVING HEAVY PRECIPITATION DISADVANTAGE ON EVERY D20 TEST

Its explicit check penalty is:

WISDOM PERCEPTION

MISTAKE 22: MAKING HEAVY PRECIPITATION AUTOMATICALLY CAUSE DIFFICULT TERRAIN

The rule doesn't say that.

MISTAKE 23: SAYING HEAVY SNOW AUTOMATICALLY EXTINGUISHES OPEN FLAMES

The specific flame rule says:

HEAVY RAIN

MISTAKE 24: MAKING A DIRECT HIGH ALTITUDE CONSTITUTION SAVE EVERY HOUR

The High Altitude entry instead makes travel hours count:

DOUBLE

for determining how long the creature can travel.

MISTAKE 25: THINKING HIGH ALTITUDE MAKES YOU TRAVEL TWICE AS FAR

It does not.

It consumes travel endurance:

TWICE AS QUICKLY

MISTAKE 26: FORGETTING ACCLIMATION

A creature can acclimate after:

30 DAYS OR MORE

at the elevation.

MISTAKE 27: LETTING ORDINARY CREATURES ACCLIMATE ABOVE 20,000 FEET

They cannot unless:

NATIVE TO SUCH ENVIRONMENTS

MISTAKE 28: THINKING SLIPPERY ICE ONLY REQUIRES A SAVE WHEN FIRST DISCOVERED

A save is triggered when the creature:

MOVES ONTO IT FOR THE FIRST TIME ON A TURN

or:

STARTS ITS TURN THERE

MISTAKE 29: FORGETTING SLIPPERY ICE IS ALSO DIFFICULT TERRAIN

It is.

MISTAKE 30: USING STRENGTH SAVE FOR SLIPPERY ICE

The save is:

DC 10 DEXTERITY

MISTAKE 31: THINKING FAILED SLIPPERY ICE SAVE DEALS DAMAGE

Failure gives:

PRONE

No damage is listed.

MISTAKE 32: APPLYING STRONG WIND DISADVANTAGE TO EVERY RANGED SPELL ATTACK

The rule specifies:

RANGED ATTACK ROLLS WITH WEAPONS

MISTAKE 33: APPLYING STRONG WIND DISADVANTAGE TO MELEE WEAPON ATTACKS

The rule specifies:

RANGED

weapon attack rolls.

MISTAKE 34: FORGETTING STRONG WIND EXTINGUISHES OPEN FLAMES

It does.

MISTAKE 35: FORGETTING STRONG WIND DISPERSES FOG

It does.

MISTAKE 36: ALLOWING A FLYING CREATURE TO REMAIN AIRBORNE IN STRONG WIND INDEFINITELY

At the end of its turn it must:

LAND

or:

FALL

MISTAKE 37: AUTOMATICALLY EXEMPTING HOVER FROM STRONG WIND

The Strong Wind rule does not list:

HOVER

as an exception.

MISTAKE 38: MAKING EVERY DESERT WIND A SANDSTORM

Strong Wind in a desert:

CAN CREATE

one.

MISTAKE 39: MAKING STRONG WIND DIFFICULT TERRAIN AUTOMATICALLY

The Environmental Effect does not say that.

MISTAKE 40: GIVING EVERY PATCH OF THIN ICE THE SAME FIXED WEIGHT LIMIT

Tolerance is:

3D10 TIMES 10 POUNDS

per:

10 FOOT SQUARE AREA

MISTAKE 41: BREAKING THIN ICE WHEN WEIGHT EQUALS ITS TOLERANCE

The weight must:

EXCEED

the tolerance.

MISTAKE 42: CHECKING ONLY ONE CHARACTER'S WEIGHT

Use:

TOTAL WEIGHT ON THE AREA

MISTAKE 43: FORGETTING WHAT IS BELOW THIN ICE

The SRD specifies:

FRIGID WATER

MISTAKE 44: DEALING AN AUTOMATIC DAMAGE ROLL WHEN THIN ICE BREAKS

The listed result is:

CREATURES FALL THROUGH

into Frigid Water.

Apply the rules actually triggered by the situation.

MISTAKE 45: MAKING EVERY ENVIRONMENTAL EFFECT DEAL DAMAGE

Many use:

EXHAUSTION

CONDITIONS

DISADVANTAGE

or:

TRAVEL MODIFIERS

instead.

MISTAKE 46: INVENTING ONE UNIVERSAL ENVIRONMENT SAVE

Each Environmental Effect has:

ITS OWN TRIGGER

ITS OWN DC

and:

ITS OWN CONSEQUENCE

MISTAKE 47: FORGETTING THAT SPECIFIC ENVIRONMENTAL RULES CAN INTERACT

A character can potentially face:

THIN ICE

then:

FRIGID WATER

then:

EXHAUSTION

You do not need to replace that sequence with:

A NEW CUSTOM HAZARD

QUICK RECAP

DEEP WATER

Threshold:

MORE THAN 100 FEET DEEP

Creature without Swim Speed:

DC 10 CONSTITUTION SAVE AFTER EACH HOUR

Failure:

1 EXHAUSTION

Swim Speed:

NO DEEP WATER SAVE FROM THIS RULE

EXTREME COLD

Threshold:

0 DEGREES FAHRENHEIT OR LOWER

Save:

DC 10 CONSTITUTION EACH HOUR

Failure:

1 EXHAUSTION

Cold Resistance or Immunity:

AUTOMATIC SUCCESS

EXTREME HEAT

Threshold:

100 DEGREES FAHRENHEIT OR HIGHER

Applies when exposed and:

WITHOUT ACCESS TO DRINKABLE WATER

First hour:

DC 5 CONSTITUTION

Additional hours:

DC PLUS 1 EACH HOUR

Failure:

1 EXHAUSTION

Medium or Heavy Armor:

DISADVANTAGE

Fire Resistance or Immunity:

AUTOMATIC SUCCESS

FRIGID WATER

Safe immersion:

CONSTITUTION SCORE IN MINUTES

After that:

DC 10 CONSTITUTION EACH ADDITIONAL MINUTE

Failure:

1 EXHAUSTION

Automatic success:

COLD RESISTANCE

COLD IMMUNITY

or:

NATURAL ICE COLD WATER ADAPTATION

HEAVY PRECIPITATION

Heavy Rain or Heavy Snowfall:

LIGHTLY OBSCURED

Creatures in area:

DISADVANTAGE ON ALL WISDOM PERCEPTION CHECKS

Heavy Rain:

EXTINGUISHES OPEN FLAMES

HIGH ALTITUDE

Threshold:

10,000 FEET OR HIGHER

Each hour traveling there counts as:

2 HOURS

for determining travel duration.

Acclimation:

30 DAYS OR MORE

Ordinary acclimation unavailable above:

20,000 FEET

unless native to such environments.

SLIPPERY ICE

DIFFICULT TERRAIN

First move onto it each turn or start turn there:

DC 10 DEXTERITY SAVE

Failure:

PRONE

STRONG WIND

DISADVANTAGE ON RANGED ATTACK ROLLS WITH WEAPONS

EXTINGUISHES OPEN FLAMES

DISPERSES FOG

Flying creature:

LAND AT END OF TURN OR FALL

Desert Strong Wind can create:

SANDSTORM

with Disadvantage on:

WISDOM PERCEPTION CHECKS

THIN ICE

Tolerance per 10 foot square:

3D10 TIMES 10 POUNDS

Total weight exceeds tolerance:

ICE BREAKS

All creatures there:

FALL THROUGH

Below:

FRIGID WATER

PRIME HERO CHALLENGE

A party of adventurers is attempting to cross a frozen mountain lake located more than 10,000 feet above sea level during a violent winter storm.

The GM determines that the following SRD Environmental Effects apply:

EXTREME COLD

HIGH ALTITUDE

HEAVY SNOWFALL

STRONG WIND

SLIPPERY ICE

and:

THIN ICE

Resolve the situation.

CHALLENGE 1: EXTREME COLD

The party spends one hour exposed to temperatures at or below:

0 DEGREES FAHRENHEIT

Each ordinary exposed creature makes:

DC 10 CONSTITUTION SAVE

Failure:

1 EXHAUSTION

CHALLENGE 2: COLD RESISTANT CHARACTER

One character has:

COLD RESISTANCE

Does that character roll?

NO

The character:

AUTOMATICALLY SUCCEEDS

CHALLENGE 3: HIGH ALTITUDE

The party travels for:

3 ACTUAL HOURS

at High Altitude.

For determining travel duration, those hours count as:

3 times 2 equals:

6 HOURS

CHALLENGE 4: HEAVY SNOW

The snowfall is Heavy Precipitation.

The area becomes:

LIGHTLY OBSCURED

Wisdom Perception checks:

DISADVANTAGE

CHALLENGE 5: BOW ATTACK

A Ranger fires a Longbow during the Strong Wind.

Attack Roll:

DISADVANTAGE

because it is a:

RANGED ATTACK ROLL WITH A WEAPON

CHALLENGE 6: SPELL ATTACK

A Wizard makes a ranged Spell Attack.

Does Strong Wind automatically impose Disadvantage from its weapon rule?

NO

The Environmental Effect specifically refers to:

RANGED ATTACK ROLLS WITH WEAPONS

CHALLENGE 7: FLYING

The Wizard gains a Fly Speed and takes off.

What must happen before the end of that turn?

LAND

Otherwise:

FALL

CHALLENGE 8: SLIPPERY ICE

The Fighter moves onto Slippery Ice.

Required:

DC 10 DEXTERITY SAVE

Failure:

PRONE

The ice is also:

DIFFICULT TERRAIN

CHALLENGE 9: THIN ICE

The GM rolls the area's tolerance.

3d10:

6

8

7

Total:

6 + 8 + 7 equals:

21

Tolerance:

21 times 10 equals:

210 POUNDS

A Fighter and equipment place:

205 POUNDS

on the area.

Does it break?

NO

205 does not exceed 210.

CHALLENGE 10: ANOTHER CHARACTER STEPS ON

An additional character adds:

90 POUNDS

Total:

205 + 90 equals:

295 POUNDS

295 exceeds:

210

Result:

THIN ICE BREAKS

All creatures on that broken area:

FALL THROUGH

CHALLENGE 11: FRIGID WATER

One of those characters has:

CONSTITUTION 13

How long can that character remain immersed without ill effects from the Frigid Water rule?

13 MINUTES

Beginning with Minute:

14

the character must make:

DC 10 CONSTITUTION SAVE EACH ADDITIONAL MINUTE

Failure:

1 EXHAUSTION

CHALLENGE 12: SWIM SPEED

Another character has:

SWIM SPEED

Does that Swim Speed automatically protect against Frigid Water?

NO

Not by itself.

Frigid Water lists automatic success for:

COLD RESISTANCE

COLD IMMUNITY

or:

NATURAL ADAPTATION TO ICE COLD WATER

CHALLENGE 13: MULTIPLE ENVIRONMENTAL EFFECTS

Can this entire sequence be resolved without inventing a new rule?

YES

The GM combines the existing procedures:

WEATHER

ICE

FALLING THROUGH

FRIGID WATER

EXHAUSTION

This is exactly why the Gameplay Toolbox is useful.

LESSON 94: KEY TAKEAWAYS

The environment can become a major part of an adventure without requiring complicated custom rules.

The SRD 5.2.1 provides nine Environmental Effects:

DEEP WATER

EXTREME COLD

EXTREME HEAT

FRIGID WATER

HEAVY PRECIPITATION

HIGH ALTITUDE

SLIPPERY ICE

STRONG WIND

and:

THIN ICE

Remember especially:

DEEP WATER BEGINS BEYOND 100 FEET OF DEPTH

CREATURES WITHOUT A SWIM SPEED RISK EXHAUSTION AFTER EACH HOUR IN DEEP WATER

EXTREME COLD BEGINS AT 0 DEGREES FAHRENHEIT OR LOWER

EXTREME COLD USES DC 10 CONSTITUTION SAVES EACH HOUR

COLD RESISTANCE OR IMMUNITY AUTOMATICALLY SUCCEEDS AGAINST EXTREME COLD

EXTREME HEAT BEGINS AT 100 DEGREES FAHRENHEIT OR HIGHER

THE EXTREME HEAT RULE REQUIRES LACK OF ACCESS TO DRINKABLE WATER

EXTREME HEAT STARTS AT DC 5 AND INCREASES BY 1 EACH ADDITIONAL HOUR

MEDIUM AND HEAVY ARMOR GIVE DISADVANTAGE ON EXTREME HEAT SAVES

FIRE RESISTANCE OR IMMUNITY AUTOMATICALLY SUCCEEDS AGAINST EXTREME HEAT

FRIGID WATER SAFE TIME USES CONSTITUTION SCORE, NOT MODIFIER

FRIGID WATER CAN REQUIRE A DC 10 CONSTITUTION SAVE EVERY ADDITIONAL MINUTE

A SWIM SPEED DOES NOT BY ITSELF GRANT AUTOMATIC SUCCESS AGAINST FRIGID WATER

HEAVY PRECIPITATION MAKES THE AREA LIGHTLY OBSCURED

HEAVY PRECIPITATION GIVES DISADVANTAGE ON WISDOM PERCEPTION CHECKS

HEAVY RAIN EXTINGUISHES OPEN FLAMES

HIGH ALTITUDE BEGINS AT 10,000 FEET

EACH HOUR OF HIGH ALTITUDE TRAVEL COUNTS AS TWO HOURS FOR TRAVEL ENDURANCE

ACCLIMATION REQUIRES 30 DAYS OR MORE

ORDINARY CREATURES CANNOT ACCLIMATE ABOVE 20,000 FEET UNLESS NATIVE TO SUCH ENVIRONMENTS

SLIPPERY ICE IS DIFFICULT TERRAIN

SLIPPERY ICE CAN CAUSE PRONE ON A FAILED DC 10 DEXTERITY SAVE

STRONG WIND GIVES DISADVANTAGE ON RANGED ATTACK ROLLS WITH WEAPONS

STRONG WIND EXTINGUISHES OPEN FLAMES AND DISPERSES FOG

FLYING CREATURES IN STRONG WIND MUST LAND AT THE END OF THEIR TURN OR FALL

DESERT STRONG WIND CAN CREATE A SANDSTORM

THIN ICE USES A RANDOM WEIGHT TOLERANCE PER 10 FOOT SQUARE

THIN ICE BREAKS ONLY WHEN TOTAL WEIGHT EXCEEDS ITS TOLERANCE

CREATURES ON BROKEN THIN ICE FALL INTO FRIGID WATER

and above all:

APPLY THE ENVIRONMENTAL EFFECT THAT THE SRD ACTUALLY DEFINES

Do not turn hostile weather into:

ARBITRARY PENALTIES

The environment becomes more interesting when the players can understand:

THE DANGER

THE MECHANIC

and:

THE CONSEQUENCES OF THEIR DECISIONS

NEXT LESSON

LESSON 95: FEAR AND MENTAL STRESS

The next Gameplay Toolbox lesson turns from threats to the body to threats against:

THE MIND

We will learn how the Game Master can represent:

SUPERNATURAL FEAR

TERRIFYING APPARITIONS

MAGICAL HORROR

INTENSE MENTAL STRESS

and:

PROLONGED PSYCHOLOGICAL EFFECTS

using the actual SRD 5.2.1 framework.

We will examine:

SAMPLE FEAR DCS

THE FRIGHTENED CONDITION AS A BASELINE

ADDITIONAL FEAR EFFECTS

PSYCHIC DAMAGE

SAMPLE MENTAL STRESS DCS

INTELLIGENCE, WISDOM, AND CHARISMA SAVES

and:

PROLONGED EFFECTS

The next lesson will also make an important Game Master principle explicit:

THESE OPTIONAL TOOLS SHOULD BE DISCUSSED WITH THE PLAYERS BEFORE THE CAMPAIGN

SRD 5.2.1 ATTRIBUTION

This work includes material from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.