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⏵ Course guide · Colorado ultra

Run Rabbit Run Course Guide

Run Rabbit Run is a big-mountain hundred (with a 50 the next day) that starts at the Steamboat ski base, climbs Mount Werner in the first handful of miles, and runs the high country of the Routt National Forest through the fall colors before a brutal little Emerald Mountain loop near the finish. It draws a stacked pro field for one of the biggest prize purses in the sport, but most of us are out there as Tortoises chasing a finish. I will walk you through the course first, then give you a pacing, night, and fueling plan that fits the altitude and the vert. There are free calculators along the way to dial in your own numbers.

⏵ At a glance

Run Rabbit Run quick facts

Date
100M: Friday, September 18, 2026 · 50M: Saturday, September 19, 2026
Location
Steamboat Resort base (Mount Werner), Routt National Forest, Steamboat Springs, CO
Distances
100 miles and 50 miles
Elevation gain
100M: roughly 16,000 to 22,000 ft (figures vary) · high point about 10,550 ft
100M start
Tortoises 9:00 AM · Hares 1:00 PM · optional early start for some Tortoise age groups
Cutoff
100M: Tortoises 36 hr (9 PM Sat), Hares 30 hr (7 PM Sat), with intermittent cutoffs · 50M: 15 hr
Qualifier
Listed as a UTMB Index race (UTMB Running Stones); confirm current qualifier status with the race

These facts come from the official race site, UltraSignup, and the published aid-station materials. The exact date, start times, cutoffs, aid stations, and elevation figures change year to year, so confirm the current race-day details before you commit.

The course: where Run Rabbit Run is won and lost

The 100 starts at the base of Steamboat Resort, climbs Mount Werner right out of the gate, then spends the day and the whole night up in the high country (Long Lake, Summit Lake, the Buffalo Pass area, Fish Creek) before dropping back to town and finishing with a punchy loop on Emerald Mountain. It is mostly mountain singletrack and dirt roads, mostly between roughly 6,600 and 10,600 feet. The day is built around the opening climb, the night, and that nasty little finish loop.

The opening climb: straight up Mount Werner

You barely get to warm up before the course points you straight up the ski mountain. The climb to the top of Mount Werner is something like 3,500 feet in the first six or seven miles, and the high point of the whole course sits up around 10,550 feet. This is where overeager people quietly wreck their race. It feels fine early because you are fresh and the views are unreal, but if you redline this climb at altitude you will pay for it with interest somewhere in the dark.

Hike the steep stuff with purpose and keep your effort honestly easy. You want to crest the top of the mountain feeling like you have not started yet. Power-hiking efficiently here, instead of grinding a slow jog, is almost always the smarter call.

The high country and the long descents

Once you are up top the course rolls through gorgeous high alpine and forest, around Long Lake and Summit Lake and over toward the Buffalo Pass area, on a mix of singletrack and dirt road. The climbing never really stops, but the part that quietly destroys legs is the descending. There are long, sustained downhills back toward town and Fish Creek, and rocky, technical drops that hammer your quads for miles.

If you have not trained downhill running, those descents will turn your quads to concrete by the time it matters. Practice controlled, runnable descending on tired legs before race day. Being able to keep moving downhill late, when everything hurts, is honestly what separates the people who finish strong from the people who shuffle it in.

The night: cold, altitude, and the lows

You will run through the entire night, and that is where the race is really decided. Up high after dark it gets genuinely cold, your world shrinks to your headlamp, your stomach gets weird, and your brain starts telling you stories about quitting. The mental low between roughly 2 and 5 in the morning is a real, predictable thing, and it is not a sign that your race is over. It is just the night.

Plan for it instead of getting ambushed. Carry real layers and a backup light, keep eating even when you do not feel like it, and lean on your pacer if you have one. Most of the time the fix is simple and boring: put on a jacket, get some calories and caffeine in, keep walking, and wait for the sun. The lows almost always lift with the daylight.

Emerald Mountain: the sting in the tail

The finish is not a gentle downhill cruise into town. Late in the race the course throws you a loop on Emerald Mountain, with punchy, steep climbing on tired legs when you are convinced you are basically done. It is a real gut-check, and there are late cutoffs through here, so you cannot crawl it.

Save something for this. If you paced Mount Werner and the night with Emerald in mind, you will get through it annoyed but fine. If you spent everything early, this is the section that turns a finish into a DNF or a death march. Respect the back half and it respects you.

Pacing strategy for a high-altitude mountain 100

With big vert, real altitude, a full night, and a stingy finish loop, Run Rabbit Run is about managing effort over a day and a half, not hitting a pace chart. Run the climbs by feel, protect your legs on the descents, and build your plan around the intermittent cutoffs.

Pace the climbs by grade, not by the watch

Your flat-ground pace is meaningless on the Mount Werner climb and the high-country rollers, especially at altitude. What matters is grade-adjusted effort, so settle on an output you can hold up the grade and hike the steep pitches without a second thought. The classic mistake here is running the opening climb hard because it feels easy, then blowing up in the night. A grade-adjusted pace turns your real flat fitness into honest climbing and hiking targets so you do not torch the first 30 miles.

Build a vert-and-altitude-aware finish prediction

Do not guess your Run Rabbit Run time off a road or rolling-trail result. The 16,000-plus feet of climbing, the altitude, the technical descending, and a full night of slowdown all add real hours. A vert-aware finish prediction gives you a realistic window and, just as important, lets you work backward into those intermittent cutoffs so you actually know how much buffer you have at each checkpoint instead of finding out the hard way at 3 AM.

⏵ Free tools to pace this course

  • Grade-adjusted pace calculator to turn your flat fitness into honest targets for the Mount Werner climb and the long descents back to town.
  • Race-time calculator for a vert-aware finish prediction on this course, so you can plan your splits against the intermittent cutoffs.
  • Race-equivalent calculator to turn a recent race result into a Run Rabbit Run goal you can actually hold over 100 miles.

Fueling strategy for the altitude and the long haul

Most Tortoises are out on this course for a full day and night, north of 24 hours, much of it at altitude where your appetite tanks. Over that long, carbohydrate, sodium, fluid, and caffeine matter as much as your fitness does. The race is often won or lost at the stomach.

Carbs: steady, trained, and stubborn

For a hundred this long, aim for roughly 60 to 90 grams of carbohydrate per hour and only push the high end if your gut is genuinely trained for it. Altitude and fatigue both kill your appetite and slow your stomach down, so the real skill is eating steadily for 24-plus hours even when nothing sounds good, not crushing big doses now and then. Practice your exact race-day carb rate on long back-to-back runs so 70 or 80 grams an hour in hour 20 feels normal instead of nauseating. When solid food stops going down, switch to liquid calories and gels and keep the carbs flowing.

Sodium, fluid, and the cold-night problem

Cover your sodium based on how you sweat, often somewhere around 400 to 700 milligrams per liter of fluid, and more if you are a heavy or salty sweater. The twist at Run Rabbit Run is the temperature swing: it can be warm and dry by day and flat cold up high at night, and people stop drinking once it gets cold and quietly dig a hole. Keep sipping after dark even when you are not thirsty. Weigh yourself before and after a long training run to find your real sweat rate, then build the plan around your own number instead of a generic table.

⏵ Build your fueling plan

Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and the Run Rabbit Run altitude and duration with the free ultra fueling calculator. Browse the rest of the free running tools at the tools hub.

⏵ Train for it with Summit Line

Get a race-day plan built around YOUR fitness, this exact Run Rabbit Run course profile, and your projected splits. Summit Line reads your real training, builds a plan for the climbing and the altitude, and rehearses your night fueling so race day is something you execute, not guess at.

Start free →Explore the demo

Run Rabbit Run FAQ

How hard is Run Rabbit Run 100?

It is a hard mountain hundred, no way around it. You climb something in the neighborhood of 16,000 to 22,000 feet (the published number moves around) over 100 miles, you start by going straight up Mount Werner for around 3,500 feet, and you spend most of the day and the whole night between roughly 6,600 and 10,600 feet of altitude. The Tortoise field gets 36 hours and the Hares get 30, with intermittent cutoffs along the way, so the time limits are generous but the altitude, the long descents, and the night are what actually break people. If you train the climbs, sleep-deprivation, and your stomach, it is very finishable.

How much climbing is in Run Rabbit Run 100?

Depending on whose track and which year you read, the 100 is somewhere around 16,000 to 22,000 feet of total gain over 100 miles, so treat it as a big-vert mountain hundred rather than a runnable one. The day opens with the long grind up Mount Werner, roughly 3,500 feet of climbing in the first six or seven miles, and the high point of the course sits around 10,550 feet. The late Emerald Mountain loop near the finish stacks on more punchy climbing when your legs are already wrecked. Always confirm the current elevation figure with the official materials, because the course and the stated numbers have changed over the years.

What is the difference between the Hares and the Tortoises?

Run Rabbit Run splits the 100 into two divisions. The Hares are the competitive, prize-money field: they start later at 1:00 PM and get a tighter 30-hour cutoff, racing for one of the largest purses in the sport. The Tortoises are everybody else, starting at 9:00 AM with a more forgiving 36-hour limit, and some older age groups can take an even earlier start. Most first-timers and most people reading a course guide are running as Tortoises, so plan around the 9:00 AM start and the 36-hour clock.

What are the cutoff times for Run Rabbit Run 100?

The overall limit is 36 hours for Tortoises (finish by about 9 PM Saturday) and 30 hours for Hares (about 7 PM Saturday), but the overall number is not the one that ends most days. There are intermittent cutoffs out on course, including ones in the late night and the Saturday morning push back over the high country and through the Emerald Mountain loop, so you cannot bank all your buffer for the end. Build your splits backward from those intermediate cutoffs, not just the finish, and confirm the exact times in the current race-day aid-station chart before you start.

How do crew, pacers, and drop bags work at Run Rabbit Run?

It is a crew-and-pacer-friendly hundred, and using both well is a big part of finishing. Pacers are allowed for the second half of the course, so line one up for the night and the final climbs when your judgement and your legs are at their worst. Crew can meet you at the road-accessible aid stations, though access up high near Buffalo Pass is restricted, so check the current crew-access map. Pack drop bags with night layers, your headlamp and a backup, fresh socks, and your own fuel, because the cold up high after dark is real and the aid you carry between stations matters more than what is on the table.

Does the altitude at Run Rabbit Run make it harder?

Yes, the altitude is a real factor and you should respect it. You spend most of the course between about 6,600 and 10,600 feet, and the high point near 10,550 feet is high enough to slow your climbing pace, blunt your appetite, and mess with your sleep and your head overnight. If you live near sea level, your climbing will feel harder and your stomach will be touchier than it is at home, so train your gut and your hiking on hills, arrive acclimatized if you can, and pace the early Mount Werner climb conservatively. Going out hard at altitude on fresh legs is the fastest way to ruin the back half.

This guide is independent and for planning only. The course details, dates, start times, cutoffs, aid stations, and elevation figures come from public sources and can change year to year, so confirm the current specifics with the official race before you register or run. The fueling and pacing advice is general and not medical advice.