A Flash Flood of Responses

Roleplaying Tips Newsletter #0781


Last week I critiqued a flash flood encounter. I asked for your feedback and ideas at the end on how you’d tweak the encounter for fun gameplay.

Below are some of the great responses I received. Thanks everyone! I appreciate the time you take to read, learn, and respond to these Musings to help us all be better GMs.

Think of the Inhabitants

From Gustavo Campanelli

For me, the most important part about the flood is that the monsters lived in there far longer than the PCs and KNOW the signs. So they also go for higher ground. This could lead to close quarters in a reduced space where not all the party can fight at once, or a fight where you have to defeat the enemy and then climb BEFORE the flood actually hits.

Save the NPC

From Joe Patterson

I love the expansion of this idea into something a bit more gameplay-oriented, Johnn. One thing I might add: NPC caught in the flood itself. Does the party strive to help him/her?

If they do, great! New NPC contact with potential plot points.

If they DON’T, they get to their destination only to discover that it ALSO was devastated by the flood, and that a prominent figure in the area is now missing, presumed taken by the flood.

The townsfolk in the area are desperate to find the NPC and inundate the PCs with questions about if they’ve seen the character in question. The PCs either have to admit letting the NPC get carried away by the flood, or they have to lie in some or fashion CONSTANTLY to keep the locals from finding out. Roleplay abounds! Well, hopefully.

Dilemmas Within Dilemmas

From Guénaël Poirier

Hi Johnn,

First I really enjoy your tips, and it made me think of new stuff and new ways to do some old stuff. So thank you.

Considering this particular point I’m half with you and half not.

The GM said his players like to be surprised, so this flood could be a pleasure for them as much as for him.

But I do agree that building the momentum with the crackling sound and making the PC search for clues will be much more interesting than just “You enter the cave, whoops flood in your teeth.” And if I were to do that I’ll go with your approach too.

In the end, you think it will just be boring dice rolls. That’s the point where I fully disagree with you. I base my view of this on my experience with my PCs, so maybe they are a unique kind or I have the chance of having really cool PC. If they run away or climb yes they will have to do a skill check, but they also go full roleplay about it.

If, on one hand, two characters don’t really like each other, then seeing the other one be better will motivate them. Seeing them fail will put them in front of a dilemma: prove your physical superiority and let the other die, or prove your moral superiority and help? If you chose the first option, the PC will save the one who failed and the run will continue. But both options will give really interesting matter for the later role play.

If, on the other hand, it’s two PCs that like each other, they will try to support each other and sort this out together.

And here comes the dilemma: if one only slows the other down, does he sacrifice himself to save his friend, or does he let his friend die because he’s afraid of dying?

In both scenarios, the dilemma is transferred to the GM once the choice is made. Do you let your PC(s) die or do you save them? In the end, whatever the choice will be for you and the PCs it will end in a good role play session after that.

For me, this flood well used could be a really interesting stone in the building of the group. And the search for the cause of the flood (because I agree with you on the fact that it can’t just happen out of nowhere) a cool side quest.

Fail Forward

From Albert Hwang

Death is a very all-or-nothing motivator. Inconvenience leads to more opportunities to roleplay, and the DM should focus on that aspect instead. Perhaps surviving the flash flood is just a skill check, but dealing with what comes after is where the roleplay opportunities lie.

Example: Did the party properly secure their backpacks? Maybe they need to scramble around a bit and find their packs, and now they’re full of silt and water and need to be cleaned out.

How about the fact that they are now soaking wet in a cold, dank cave, and at risk of hypothermia? Do they build a fire and warm up, or do they use magic to get themselves clean and dry and press on? Maybe one character decides to brazenly strip to underwear and hang up their clothes to dry, which might offend the prudish cleric — a roleplay opportunity right there. The DM can sit back a bit and let the players carry the conversation for a bit, and the players can add nuance to their characters.

Next up, the inconvenience should affect another encounter. Maybe while everyone is changing clothes and getting dry (and therefore, not wearing their armor or carrying their weapons), that’s when some bandits decide to come by and try to strong arm them. Maybe instead of bandits, it’s a local lord and their retainers, who saw the flash flood happen and decided to see if anyone got caught in it (a common occurrence) and now the party has to do a social encounter while soaking wet and shivering cold and covered in mud.

My second thought is it’s not necessarily bad for the DM to stroke their ego a bit and enjoy seeing the players struggle with adversity. But the players should be allowed just as many opportunities to stroke their own egos and feel like badasses. Maybe a session or two down the line, the party ends up in a battle in a ravine.

First, someone notices the ground is silty and there’s a characteristic scent of rotting fish. Then someone else notices storm clouds on the horizon. Then a low rumble and the feeling of whooshing air…the bad guys are looking confused at all of this, but the party knows what’s going to happen and can quickly climb to safety moments before a massive flash flood sweeps the orcs downstream in a torrent of water! Or maybe the enemy also knows about the flash floods, and start to climb. Now the fight becomes a struggle to knock each other into the course of the oncoming flash flood, much more interesting than a plain stand-and-fight encounter.

Invisible Threads

From Joshua Barry

I do a lot of hidden deity stuff in my campaign, so when I read the flash flood, I think it was part of the prophesy of when the river returns to the desert.

Evil comes in many forms. And in my head the Goddess of Mold and Slime has been locked away in a watery cell inside a mountain in the desert.

Some jackass just broke part of her prison, starting to release her. Of course, the players are loaded out for desert survival and not for a swim.

So immediate issues are gear and key items getting wet or washed away. Long term is about this goddess being free. Middle ground is a small cult of farmers will develop due to the blessings of the river.

Save the MacGuffin

From Jerry Anning

How about the Abu Simbel option?

When Nasser greenlit the Aswan Dam, archaeologists scrambled to rescue and move as much as they could of the temple of Abu Simbel before it was inundated.

Somewhere lower in the cavern, there is an area containing info/hostages/macguffins/artifacts/loot. The players have to get there quickly while dealing with the obstacle presented by the flood, and rescue/recover what they can before it is drowned, destroyed, or buried under debris.

The Inciting Incident

From Joe Reed

As a desert dweller myself, the prospect of flash floods is terrifying. We see them every few years. An interesting part is it doesn’t need to be raining where you are. Clues before the encounter can include storms in the distance, especially on the mountain, or news of major rainfall in the next kingdom over.

These kinds of clues beforehand can help it feel like less of a GM gotcha. Any party members from the desert or badlands can recognize the signs.

To make it fun the party needs meaningful choices. The flood means they have to make those choices swiftly, but it doesn’t create choices by itself.

What’s in the water, though? Someone to be saved? In my game, orcs and goblins aren’t inherently evil, but they are often enemies of the party. If an orc or two are in the water, do you try to save them? What about a rival adventurer? Or a bound prisoner?

If the party is able to overcome the surprise (and they SHOULD be able to, otherwise it’s decidedly NOT fun) then what? The flood lasts several hours at least, if not days. Their footpath has become rapids. Are they stuck on a ledge until it passes? Not very heroic or adventurous. Previously blocked passages may have opened. New creatures may have stirred. Everything is scrambling to respond to this threat. Rescuing loved ones and possessions. Mourning their losses. Is now the time to strike? To help? Did someone destroy a dam to cause this problem on purpose? What are they up to?

You’re right. This is a better inciting incident.

Work Backwards

From Wayne Van Stanley

You’ve covered excellent plot and action elements necessary to make this more of a memorable and enjoyable encounter, Johnn.

My main question is: Why would there be a dry wash in a cavern in the first place?

Please understand, in a fantasy setting most anything goes as long as you have a good explanation or backstory. For example, if you want to have water run uphill, it could be because of some magic or one of the “sciences” of fantasy realms. And then create a historical or legendary backstory the PCs can learn in order to explain it.

This brings me to the cavern ‘wash’.

First, my original question: Why would there be a dry wash in a cavern in the first place?

Is this some hopeful egress into the “outside world” after a long campaign under the earth? Let’s presume that it is.

Then: Why would a wash go through a mountain or cliffside?

With a good backstory, this could be even cooler to play. Of course, previous to coming to the wash, I would suppose they would need an encounter where, frustrated with being in this cavern for so long, they would need to pry information out of a “local” denizen of this stony underworld. With that, and offering an idea involving “natural” phenomena, I offer…

The backstory given by said informant could be: “From high above us, sometimes the snow-capped peak of Mt. ______________ melts in a matter of a mere day. When this happens, what we call the Back Door out of these caverns takes in the onrush of this melted snow. It is then funnelled in by the Deep Valley between two of the great, ridged arms of the mountain. When this happens none go near the Great Dry Wash. But, unless you want to go all the way back through the caverns to where you came in, it is the only other way out of here.”

Now, you got an encounter that makes for tension, drama, potential and immediate action, and a sense of impending doom. The PCs know this could not only be very dangerous, but even deadly. However, as the denizen said, it’s the only other way out!

Now, all those other encounter elements you mentioned, Johnn, become even more important to note and urgent to consider.

And like you said, all encounters have to be worked backwards…from the end result (pro or con) to the starting point. Actually, a whole dungeon campaign, even a one shot scenario, should be approached the same way.

A Truce

From Jay A. Johnson


I like your idea of: “Therefore, add details about the upcoming danger. Describe how the cavern looks because there’s been flash floods before. Provide clues for players to noodle on.”

I’d go further. Having seen flash floods in rocky and desert conditions before, I would add several additional hints about the coming hazard. If the canyon the PCs are in runs east/west, describe the ominous dark clouds in the western sky. Let the players see tremendous cloud to cloud lightning in the distance and the rumble of thunder as it shakes the ground. Before the flash flood hits, have some smaller rocks tumble into the canyon — not for damage, but as a foreshadowing of the strength of the water coming towards them.

Then I’d give them more than two choices about where to go. I like the idea of a ledge with an empty cave to the west. It sets up a dilemma. Can we make it to safety (the empty cave) by heading towards the oncoming disaster?

The use of grapples and ropes is also good, but only if the PC’s have them and remember to use them. Perhaps there may also be a place of safety inside the cave just ahead. That place may already have occupants. Maybe NPCs, maybe monsters.

But, what if the denizens in the caves ahead have an unwritten rule about a temporary truce and that they will let anyone use the ledge when a flash flood comes down the canyon? Imagine the players’ surprise when a family of manticores reaches down to help the party get out of the way of the flash flood.

But the truce is only temporary. After the flood, the manticores fly back to their cave and if the PCs later find them, then it’s still a fight with no previous regard for what happened during the flash flood.

Not knowing the levels/gear of the PC’s, it’s hard to give advice about what they could do. If flying or levitating is an option, then saving the party may be as easy as using a couple of spells. The higher the level of the PC’s typically the more options they have. Even so, the players might not think about spell combinations if they are not given much time.

I’d make sure there are at least 3 mundane options the players can use to avoid the flash flood. I’d go with one behind, one ahead, and one close by. Perhaps a stout rock or tree they can lasso. Or two trails that lead out of the canyon, one on the north side and another on the south, but both trails are narrow and might not allow enough time for the whole party to get out of the way if they all only choose one. The party may have to split up and end up on opposite sides of a raging torrent. Again another dilemma.

These are great ideas, everyone. Thanks again for your emails and suggestions. I especially like the thinking behind the tweaks for how to make an encounter more fun for both GM and players. See you all next Musing!