Crawling Ever Upwards
Using Depth Crawls to Climb Mountains
This ruleset leans almost entirely on the
article Craft Killer Climbs with some procedural approach taken from Justin Alexander’s article on Depth Crawls on his blog The Alexandrian. Luke came up with some genius but simple mechanics to simulate the hazards of climbing. He built those mechanics around a topgraphical hex mapping procedure he detailed in Hexelevation.As is my wont, I was spitballing ideas on his discord and hit on the idea of linking these rules to a depth crawl. One that could provide a template for GM’s that want to run a perilous and cinematic ascent up an unforgiving mountain.
So, what do we need to build a Depth Crawl? I’ve already taken a crack at building one before but lets lay down some of our building blocks.
Not sure what a Depth Crawl is? Skeleton Code Machine has you covered.
Tracking Depth?
We’re going up, not down. Lets call our tracking element Elevation (there will be rolls relating to Altitude Sickness so calling for Altitude checks could be confusing). I don’t want this to be massive, but lets go with twenty-five locations and call our climb complete at Elevation 25. We can group our locations into five regions - foothills, lower slopes, middle slopes, higher reaches and the summit.
Randomisation
When climbing to a new Elevation Level we’ll make an Elevation Check, rolling a d12 plus Elevation and comparing it to our Location Table. You could use different sizes of dice to make your climb longer or shorter and to give more variance of results. For smaller ascents, the Location Table can be very granular with every result being a new location. For higher ascents, it’s recommended to use ranges of locations - e.g. 1-5, 6-10, rather than describing 90 locations on your fictional Everest.
Altitude
The Elevation level is left purposely abstract as a tracking measure, but you could say that the Elevation check result mutiplied by 100 is the height in metres. Ben Nevis would be an Elevation 15 mountain. Everest would be almost Elevation 90.
Time
Each day is divided into four Watches (morning, afternoon, evening, night). The GM should track this during the ascent. Every two increments of Elevation moves time forward by one Watch.
Procedure
Start at the Base location at Elevation 0. Record this on the bottom of a map as you would the first point in a point crawl.
Roll on the Weather
Make a Climbing check. Apply results.
Make an Elevation check on the Locations table(You start at Elevation 0.)
Make a Elevation Check on the Details table (You start at Elevation 0.)
This is the location where the PCs enter the ascent.
On each navigation turn, the PCs will choose one of three moves:
STAY
CLIMB HIGHER
CLIMB DOWN
If they STAY, they are remaining in their current location. Follow your normal procedures for that location.
Make an encounter check. Use an appropriate terrain based encounter table for your system.
If they CLIMB HIGHER:
Make a Climbing check. Apply results.
Draw a line upward to a new location on your pointcrawl map.
Increase the group’s Elevation by one increment.
Every two increments of Elevation moves time forward by one Watch.
Draw a line upward to a new location on your pointcrawl map.
Make a Elevation check on the Locations
Make a Elevation check on the Details
If required, roll on Weather.
Make an encounter check.
Note results and elevation on your map (important for backtracking!)
If they GO BACK, they travel along a path they’ve already explored to a location they’ve previously visited:
Set the group’s depth to the established depth of the location.
Make an encounter check.
Steep Climbs and Multiple Routes
As an optional rule, the GM can roll 1d3 for the Elevation increment of the next Location. A higher number represents a steep and risky climb.
Another option that can be used has the GM could roll d3 for the number of routes upward and assign an Elevation increment of d3 for each. This gives players risk-based choices: take a route without steep gradients (probably longer), or take the risk and climb a sheer ascent for swifter progress.
Climbing checks
A climbing check is modified by the target Elevation value you are climbing to. Roll a d20 roll, where you need to roll above the target Elevation to climb without incident. If ascending from 0 to 1, don’t roll a one. From 4 to 5, don’t roll below a 6. From 10 to 11, don’t roll below a 12.
Remember your P’s! Proper Preparation Prevents Piss-Poor Performance. For example, if taking take a watch to observe the route (provided visibility allows), roll the check with advantage. If the weather presents low visibility, checks are at a disadvantage.
For a failed check, consult the following table.
Climbing Incidents (d8):
1: Fall d100ft. Use fall damage in whatever game system you are using.
2: Slip and sprain an ankle. Speed halved until healed.
3: Rock fall. 1d6 bludgeoning damage.
4: Gear slips away from you. Lose an item.
5: Exhaustion. Must rest immediately after completing the climb.
6: Vertigo. One of the party starts to panic. Disadvantage on rolls until calm.
7: Impassable Route. Return to previous location. Lose D4-1 Elevation.
8: Lost. Generate a Location at their new depth, unconnected to any known location.
Altitude Sickness
Many humans start to struggle at altitudes over 2km, as oxygen deprivation takes its toll. When characters arrive at a location via an Elevation check of 20 or above, have them make a relevant physical health check for the first two watches at that altitude.
If they fail, have them roll an effect on an altitude sickness table, like this:
Altitude Sickness (d4):
1: Confusion. Disadvantage on mental checks.
2: Breathless. Speed halved.
3: Weakness. Disadvantage on physical checks.
4: Sick. Take 1d4 damage from vomiting every watch.
This effect lasts until they shake the altitude sickness. They keep rolling on every watch until they succeed or descend to a safe altitude. These effects stack with subsequent failures, but you can waive that if you want to be a coward.
When the characters ascend further, they continue to make checks every 10 point increment (level 30+, level 40+ and so on). It’s worth noting that at a location check result of 50 (5km), most people require supplemental oxygen to avoid lethal hypoxia.
Weather
Make a weather table that suits the biome, with the harsh results assigned to higher numbers. A d20 table works well for this.
Roll once per day in lowlands (altitude 0), but once per watch (morning, afternoon, evening, night) in highlands (anything above 0) to simulate the changeability of weather at high altitude. See the example below, where compromised visibility means disadvantage on climbing checks:
Weather (d20):
1-5: Clear.
6-10: Overcast.
11-15: Rain.
16-18: Fog/snow (low visibility).
19-20: Storm/blizzard/gale (low visibility, 1 damage per hour if unsheltered).
You could rule that cold weather clothing reduces damage for a watch. Build in whatever effects fit the weather you like.
Locations
There’s random tables all over the place for generating mountain environments. I read over some for inspiration and made a location list of 25 locations. When rolling an Elevation Check for Location, compare with the below. Note some of the locations are hazardous, making climbing difficult or have a tendency to have inclement weather. You can expand on or substitute your own locations, but the below gives a pretty good framework for a mountain ascent with some varied terrain and features.
Foothills (Elevation 1–5)
The Trail Begins. A dirt track ends at a small clearing where climbers gather before heading into the range.
Orchard in the Valley. Rows of apple trees at the mountain’s base, dry stone walls crumbling in places. A farmhouse smokes faintly in the distance.
Dry Bed. A rocky creek bed, usually dry except when the snowmelt fills it. The stones are polished smooth by sudden torrents.
Shepherd’s Pasture. Sheep graze on grassy slopes. Scraps of wool cling to thornbushes.
Old Road Remnant. A line of sunken stones hints at a road long since swallowed by scrub. Cart ruts are still visible in patches.
Lower Slopes (Elevation 6–10)
Timber Cut Site. A half-overgrown logging camp with rusting saws and collapsed shacks. Saplings reclaim the clearing.
Mountain Spring. Clear water bubbles from beneath a rock ledge, collected in a log trough. Smells of wet stone and pine.
Abandoned Cabin. A weather-beaten hut leans against a cliff. Inside: a broken stove, rotted bedding, and dust.
Steep Switchbacks. The trail climbs in sharp zigzags. Loose gravel shifts dangerously with every step. Next Climb check at disadvantage.
Game Trail Junction. Narrow tracks converge at a salt lick. Deer and boar spoor is fresh and faint paw prints linger too.
Middle Slopes (Elevation 11–15)
Stone Quarry. A long-abandoned pit, blocks of half-shaped granite scattered.
Riverside Gorge. A foaming torrent carves a deep gorge across the slope. The only crossing is a fallen tree, slick with spray. Disadvantage on next Climb check.
Hunter’s Camp. A ring of blackened stones beneath an overhang. Bones of deer and goat cracked for marrow. Racks for drying hides.
Rock Shelter. A shallow cave used by shepherds or hunters in storms. Smoke stains mark the roof.
Ridge Overlook. A grassy shelf opens to sweeping views of the valley. Cairns of stacked stones mark the edge.
Higher Reaches (Elevation 16–20)
Avalanche Chute. A scar of crushed trees and boulders cuts the mountainside. The slope above looks unstable. Disadvantage on next Climb Checks. Loud noises may trigger avalanche.
Wind-Scoured Ridge. Twisted pines cling to a knife-edge ridge. The wind howls so loud it drowns speech. Roll twice on Weather table and use highest result.
Alpine Tarn. A small lake mirrors the sky. Snowmelt trickles in, trout flash in the icy waters.
Sheer Cliff Face. The trail ends at a vertical wall streaked with ice. Only climbers with gear could ascend. Make next Climb check with disadvantage. Roll twice on the climbing incident table on a failed check and take the lowest result.
Goatherd’s Pen. A rough stone enclosure sits against a slope, dung and bones scattered inside.
Summit & Crown (Elevation 21–25)
Snowfield Crossing. A hard crust of snow stretches across the slope. Meltwater runs in hollow channels beneath.
Glacial Moraine. A crescent of boulders and gravel left by retreating ice. Stones grind underfoot like loose glass.
Exposed Summit Shoulder. High winds scour a barren plateau of shattered stone. Lightning scars blacken the rocks. Roll twice on weather table. Pick highest result.
Cairn Cluster. Dozens of small stone cairns dot the ridge, stacked by climbers or herders. Some toppled by storms.
The Peak. A bare crown of frost-rimed rock, horizon spilling in every direction. The view is incredible. Thin air burns the lungs. It tastes of victory.
Details
Details either add to or change twist the nature of locations. These might be individual elements (e.g., a cart or a cairn) or they could be broadly thematic (e.g., aurora borealis or a deep ravine), with the former generally being additions to the scene and the latter usually altering it. The Details below provide a good range of generic and foreboding results but you could alter them depending on theme - perhaps more horror or supernatural with flayed skulls or wraith haunted cairns. Alternatively you could lean more fantasy with wyvern nests or enchanted groves. Roll an Elevation Check to determine a a Detail for a scene. Optionally, roll d3 Details.
A mossy boundary stone carved with half-legible initials.
A ruined shepherd’s cart, wheel sunk deep in mud.
A thicket of blackberries conceals torn cloth, snagged and bloodstained.
A clearing of wildflowers, humming with bees.
A half-collapsed wooden footbridge spans a shallow gully, rotten planks breaking under weight.
A hollow tree shrine with wax stubs melted into unsettling shapes.
A cluster of fire-scorched stumps, ground still unstable with hidden hot ash vents.
A ravine crossed by the remains of a rope bridge, frayed strands swaying in the wind.
A pile of neatly stacked firewood with a half-buried boot jutting from underneath.
A stand of unusually tall pines, their trunks stripped bare at the base by deer.
A narrow ledge strewn with loose scree that shifts underfoot with each step.
A rusted iron kettle hanging from a branch, rattling faintly though no wind blows.
A field of alpine flowers, startlingly vivid against bare rock.
A shallow cave littered with bones, not from birds, but from something larger.
A spring-fed pool iced over, with a pale shape just visible beneath the surface.
A cliff face patterned with white mineral streaks like frozen waterfalls.
A line of crude cairns, each topped with an animal skull staring downslope.
A lurid glow of aurora borealis illuminates the sky.
A scree slope with the corpse of a pack animal, loose stones ready to cascade.
A natural rock arch where the wind makes low, human-like moans at night.
A jagged ravine. Deep, dark and probably fatal.
A field of shattered boulders arranged in spirals, casting uncanny shadows.
A knife-edge ridge where gusts scream through like voices.
A circle of frost-hardened stones, a foetal skeleton frozen in the centre.
A patch of ice that never melts, faint cracks revealing a baleful eye staring upward.
Final Thoughts
This little essay was mainly to get the idea out of my head whilst its fresh but I also plan to try it in an upcoming game and wanted to organise my thoughts. If you like it or get some use out of it, let me know!
I’ve already mentioned him but full credit to
for teaching me everything I know about Depth Crawls, for coming up with all the various checks and challenges and for providing such a cool space to bounce ideas around. I know he’s got more on this topic bubbling away so look forward to see if he takes this further and where he goes with it.
Love this! One of my favorite topics so I’ll have to think about using this system