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⏵ Course guide · Oregon ultra

Three Sisters Skyline Course Guide

The Three Sisters Skyline is Alpine Running’s high-Cascade 50K out of Sisters, Oregon, and it is honestly one of the prettier, more runnable mountain 50Ks you can pick. You climb a long, patient grade up to the edge of the Three Sisters Wilderness with the peaks standing right in front of you, then the whole back half tips downhill toward town. I will walk you through the course first, then give you a pacing and fueling plan that fits the front-loaded climb and the long descent. There are free calculators along the way to dial in your own numbers.

⏵ At a glance

Three Sisters Skyline quick facts

Date
Saturday, September 19, 2026 (third Saturday of September)
Location
Start at Village Green Park, Sisters, Oregon, on the edge of the Three Sisters Wilderness
Distances
50K (about 31 mi) and a point-to-point Half Marathon
Elevation gain
50K: organizer lists ~3,700 ft gain / ~4,700 ft loss (UTMB/ITRA measure it near 880 to 890 m, ~2,900 ft) · Half: ~500 ft gain / ~1,500 ft net downhill
Start
50K at 8:00 AM · Half Marathon at 9:30 AM
Cutoff
50K: about 9 hours (per ITRA); confirm the current limit with the race
Aid / qualifier
50K: 3 fully stocked aid stations · UTMB Index race that earns UTMB Running Stones

These facts come from the official race site, UltraSignup, and the UTMB / ITRA listings. The organizer’s GPS gain and the official measured gain differ a little, so I show both. Check the current date, cutoff, and aid stations in the race-day details before you commit. Race logistics change year to year.

The course: where Three Sisters Skyline is won and lost

The 50K runs from Village Green Park out toward the Three Sisters Wilderness and back, about 31 miles on roughly 95 percent single track. The shape of the day is simple: climb steadily for the first third, top out near the Wilderness boundary with the peaks in your face, then ride a long net descent home. The race is mostly won by how patiently you climb and how well your quads survive the back half.

The opening climb: long, steady, and easy to overcook

The first 9.7 miles or so are one long, gradual grind, roughly 2,300 feet of gain, up through ponderosa forest and the regrowth from the 2012 Pole Creek burn to the first aid station near the Wilderness edge. It almost never gets truly steep, and that is exactly the trap. The grade is gentle enough that you can run most of it, so the temptation is to hammer the climb because it feels totally doable in the cool morning air.

Do not. This is where the race is quietly won or lost. Settle into a steady, conversational effort, hike the few stiffer pitches if it keeps your heart rate down, and arrive at the top with your legs intact. The reward is real: as you crest toward the Wilderness boundary the Three Sisters open up dead ahead, and you still have plenty in the tank to use them.

The high country and the net-downhill back half

Up top the course rolls through open alpine meadow and high single track with those head-on Three Sisters views, then it turns for home and trends downhill most of the rest of the way. The organizer lists about 4,700 feet of total descent against roughly 3,700 of gain, so you end up lower than you climbed. That net drop is a gift if you paced the climb right and a punishment if you did not.

Long, runnable downhill on single track is fast, but it chews up quads that are already tired or undertrained. The people who blew the climb spend these last miles in a slow, braking shuffle. The people who held back early get to actually open up and run the descent. Practicing controlled downhill running before race day is the single biggest thing that separates a good finish here from a survival march.

Altitude, exposure, and the three aid stations

The 50K has 3 fully stocked aid stations, with the first up near the high point around mile 9.7, so plan to be self-sufficient across each leg rather than assuming the next table is close. Carry enough fluid and calories to cover the gaps, especially the climb to that first stop.

This is high Cascade terrain, so the air is thinner up top and the meadows are exposed to full sun by midday even when the morning started cold. The footing is mostly smooth, runnable single track, not a rock scramble, but the altitude and the open exposure are real factors. Treat them as part of your plan from the gun, not a surprise you deal with on the day.

Pacing strategy for a front-loaded climb and a long descent

With the climbing stacked into the first 9 to 10 miles and a net descent home, Three Sisters Skyline is all about effort management. Run the opening grade by feel, not by your flat-ground splits, and save your legs for the part of the course that pays out: the way back down.

Pace the climb by grade, not by the watch

Your flat-ground pace is meaningless on the long opening climb. What matters is grade-adjusted effort, so hold a steady, sustainable output up the grade and let your pace per mile slow without stressing about it. The classic Three Sisters Skyline mistake is running that gentle climb too hard because it feels easy at altitude in the cool morning, then arriving up top already cooked for the descent. Use a grade-adjusted pace to turn your real fitness into honest climbing and descending targets, and you will not torch the first third of the race.

Build a finish prediction off this exact profile

Do not guess your Three Sisters Skyline finish off a flat road 50K time. The front-loaded climb, the altitude, and the long net descent all change the math, and the descent can actually claw time back if your quads hold. A finish prediction built off this course’s climbing and descent gives you a realistic window, lets you check it against the roughly 9-hour cutoff, and tells you how hard you can press the back half without blowing up.

⏵ Free tools to pace this course

Fueling strategy for an alpine September 50K

Most runners are out on the Three Sisters Skyline 50K for somewhere around 5 to 8 hours, climbing early and descending late, with only three aid stations and some real altitude up high. That makes carbohydrate, sodium, and fluid just as important as your legs.

Carbs: steady and trained, especially on the climb

For a 5 to 8 hour effort, aim for around 60 to 90 grams of carbohydrate per hour, and only push the high end if your gut is trained for it. Get most of it in early on the long climb while your stomach is happy and the effort is controlled, because it is much harder to eat when you are pounding the descent late in the day. Practice your exact race-day carb rate on long climbing runs so 70 to 90 grams an hour feels normal, not like an experiment you are running for the first time on course.

Sodium and fluid: cool start, exposed and thin up high

The morning start is usually cool, so you may sip lightly early, but do not let that fool you: the high meadows are sun-exposed by midday and the air is thin, which quietly drives up fluid and sodium needs on the back half. A common range is around 300 to 700 milligrams of sodium per liter of fluid, leaning higher if you are a heavy or salty sweater. Carry enough to cover the legs between the three aid stations, especially the climb to the first one. Weigh yourself before and after a long run to find your real sweat rate, then build the plan around your own number instead of a generic guess.

⏵ Build your fueling plan

Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and this alpine 50K 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 Three Sisters Skyline course profile, and your projected splits. Summit Line reads your real training, builds a plan for the front-loaded climb and the long descent, and rehearses your fueling so race day is something you execute, not guess at.

Start free →Explore the demo

Three Sisters Skyline FAQ

How hard is the Three Sisters Skyline 50K?

It is a real mountain 50K, but it is one of the friendlier ones in the high Cascades. You climb a long, steady grade for the first 9 to 10 miles up to the Three Sisters Wilderness edge, then the course tips net downhill all the way home. The organizer lists roughly 3,700 feet of gain and 4,700 feet of loss over about 31 miles, while UTMB and ITRA measure the official gain closer to 2,900 feet, so the climbing is moderate by ultra standards. The hard parts are altitude, exposure up high, and saving your quads for a long descent, not one brutal wall.

How much climbing is in the Three Sisters Skyline 50K?

The race organizer puts it at about 3,700 feet of gain and 4,700 feet of loss across the 50K, and the UTMB Index / ITRA listing logs the measured climb nearer 880 to 890 meters, which is roughly 2,900 feet. Either way, most of the climbing is front-loaded: the first 9.7 miles are a slow, steady grind of around 2,300 feet up to the first aid station near the Wilderness boundary. After that the course is more of a net descent back toward Sisters, which is why the half marathon version is run point to point with a net downhill.

What is the cutoff for the Three Sisters Skyline 50K?

The 50K time limit is listed at about 9 hours on the ITRA record for the race, which is generous for the distance and the moderate climbing. There do not appear to be tight intermediate cutoffs published, but you should still plan to clear the first aid station with margin. Race logistics change year to year, so confirm the current overall and any intermittent cutoffs with Alpine Running before you start.

Is the Three Sisters Skyline a UTMB qualifier?

Yes. The 50K is a UTMB Index race, which means a finish counts toward your UTMB Index and earns UTMB Running Stones for the World Series lottery. Under the current 50K Running Stones policy that is 2 stones for finishing, though UTMB sets the exact stone count and you should confirm it for the year you run. If chasing a UTMB start is part of your plan, this is a scenic, runnable way to bank an Index result.

What is the terrain and weather like at Three Sisters Skyline?

About 95 percent of the 50K is on single track. You run through ponderosa pine forest, past the regrowth from the 2012 Pole Creek fire, and into open alpine meadow with the Three Sisters standing right in front of you near the high point. Mid-September in the high Cascades usually means a cool, crisp morning start and a warmer, sun-exposed afternoon up high, with thinner air at altitude. Late-season smoke or an early cold snap is always possible, so check the forecast and the air quality in the days before.

Is the Three Sisters Skyline a good first 50K?

It is one of the better first 50Ks in the Pacific Northwest. The climbing is moderate, the footing is mostly runnable single track, the cutoff is forgiving near 9 hours, and the net-downhill back half rewards patience early. The catch is that you have to respect the front-loaded climb and the altitude, and you need quads that can take a long descent late in the day. Train the climbs and the downhills, rehearse your fueling, and a prepared first-timer has plenty of room to finish.

This guide is independent and for planning only. The course details, dates, cutoff, aid stations, and qualifier status 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.