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⏵ Course guide · Free

FOURmidable Course Guide

FOURmidable is a steep 50K in the Sierra foothills near Auburn and Cool, and it runs on the historic Western States trail. You get four major climbs, over 6,000 feet of gain, a bunch of river descents, and a cool February day that is sometimes muddy. I will walk you through the course, then give you pacing and fueling that is built for those exact conditions. There are free tools to dial in your own numbers too.

⏵ Quick facts

FOURmidable at a glance

Date
Sat, February 20, 2027 (50K starts 8:00 AM)
Location
Sierra foothills near Auburn / Cool, CA (Gold Country)
Start / Finish
Overlook Park, Auburn (855 Pacific Ave)
Distances
50K, 35K (about 22 mi), Half+, and 13K, all same day
Elevation gain
Over 6,000 ft of climb on the 50K (Strava reads about 5,947 ft)
The four climbs
Cardiac Hill, K2 (Training Hill), Knickerbocker, and the Overlook climb
Aid / cutoffs
Several aid stations with firm cutoffs near a 16:30 per mile pace
Surface
100% unpaved, under 1 mile of road on any distance

One note: all the FOURmidable distances run on the same day, with staggered starts from Overlook Park. Course details, aid stations, and the exact cutoff clock times can change year to year, so always confirm the current date, route, and cutoffs on the official FOURmidable race site before you plan your race.

The course

The FOURmidable 50K starts and finishes at Overlook Park in Auburn, and it threads the American River canyons on sections of the historic Western States trail, including the famous No Hands Bridge. It is almost all unpaved, with under a mile of road. And it is built around four major climbs that give the race its name: over 6,000 feet of cumulative gain (Strava tracks read around 5,947 feet) packed into roughly 31 miles of steep up and down.

Cardiac Hill sets the tone early

The 50K drops off the rim toward the river early, then climbs back up Cardiac Hill, the first of the four named climbs, while your legs are still fresh. And that is exactly the trap. A hard climb this early feels easy to attack, and attacking it is how runners get to the back half climbs already cooked. Hike the steep pitches with purpose and save your running legs for the runnable, rolling sections.

After the opening loop you come back through the start area aid near Gate 142 to refuel, and then you head out toward No Hands Bridge and the bigger middle climbs. Treat this early part as setup. It is not a place to bank time.

K2, the canyons, and No Hands Bridge

From No Hands Bridge the course climbs K2, the so-called Training Hill, up toward the top of Knickerbocker Canyon, then plunges all the way back down to the river. This is the heart of FOURmidable. You hit repeated steep canyon walls where you climb hard, drop hard to the water, and climb again. The descents to the river are where your quads get quietly destroyed if you let gravity do the driving.

You then grind the switchbacks back up to the Knickerbocker aid station and cross Knickerbocker Creek on your way toward Cool. Footing matters here. The canyon singletrack can be loose or muddy after February rain, so run the descents controlled and light, not reckless.

Cool, the Western States trail, and the final climb

Past the Cool aid station, the route follows the Western States trail back toward the No Hands area and then up to the finish. By now you have spent the whole day on steep, repetitive terrain, and the last climb back up to Overlook is where a race that felt fine gets real. The runners who held back on the early Cardiac and K2 descents still have legs for this final pull. The ones who did not are stuck in a slow march.

The whole back half rewards patience. Keep eating, keep your effort honest on the climbs, and hold just enough in the legs to run the last approach to Overlook Park instead of survive it.

Aid stations and cutoffs

The 50K is supported by several aid stations, including Gate 142, No Hands, Knickerbocker, and Cool. They are stocked with the usual ultra stuff: soda, boiled potatoes, candy, gels, electrolyte, and salt tablets. The intermediate cutoffs are firm and run close to a 16 to 16:47 per mile pace at the major checkpoints.

Because the cutoffs sit near that 16:30 per mile band on a course with over 6,000 feet of climbing, you cannot hike the front half casually. Check the official FOURmidable checkpoint cutoff chart for the current year and build your pacing plan backward from those times with a buffer. The climbs and any mud will slow you more than a flat course would.

Pacing strategy for FOURmidable

A four-climb, 6,000-foot 50K rewards patience and punishes ego. Pace this course by effort and by grade, not by the flat-ground numbers from your home training runs. And respect the firm cutoffs.

Pace the climbs by grade, not by clock

On a course with over 6,000 feet of gain in roughly 31 miles, your moving pace is going to swing all over the place between the steep climbs and the runnable sections, and that is fine. Power hike Cardiac, K2, Knickerbocker, and the Overlook climb, and run the gentler grades. Trying to hold a steady minutes-per-mile number across terrain like this is a fast way to overcook the early climbs and have nothing left for the final pull.

Use our free grade-adjusted pace calculator to turn your flat fitness into honest effort targets for the steep FOURmidable climbs. Then you know whether you are pacing the vertical sustainably or burning matches you will need late. Learning to power hike well, and using poles if the rules allow, is some of the most race-specific work you can do here, and our power hiking and poles guide covers it.

Protect your quads for the river descents

FOURmidable is not decided on the climbs alone. The course drops to the American River over and over and then climbs back out, so the downhill running is the hidden crux. Hold back on the early descents, run them controlled and light instead of letting gravity hammer your legs, and your back half is going to be a lot better. The runners who finish strong are usually the ones who still have working quads on the final Overlook climb. The climbs are not what get you. The descents are.

To set a finish goal that actually accounts for all that vertical, use our vert-aware race time calculator. It factors the climbing into your projected finish, so you are not stuck on a flat-course estimate that the canyons will quietly demolish. Our guide to training for elevation gain and vert shows how to build the legs that hold up on this profile.

Beat the cutoffs with margin

Because the intermediate cutoffs sit near a 16:30 per mile pace on steep terrain, you cannot drift. Run the runnable sections honestly and keep your aid-station stops short so the clock does not creep up on you at Knickerbocker or Cool. The balance to strike is banking a sensible buffer early without redlining the climbs.

If you want to reality-check your goal before you commit to a number, our race equivalent calculator turns a recent race result into an equivalent effort. And our broader guide on how to pace an ultramarathon by effort lays out the by-feel approach that works best on a course this steep.

Fueling strategy for FOURmidable

A steep, three to seven hour effort in cool February air makes fueling discipline matter as much as fitness. Heat is rarely the limiter here. The bigger risk is just forgetting to eat and drink in the cold while you grind the climbs.

Carbs: ramp to the high end, on a trained gut

For an effort this long and this hilly, target roughly 60 to 90 grams of carbohydrate per hour, and lean toward the high end once your gut is trained to handle it. Use a glucose-plus-fructose blend so you can absorb more than a single sugar lets you. And rehearse your exact hourly carb number on long training runs so 80 to 90 g/h feels normal, not experimental, by race day. Our guide on how many carbs per hour for an ultramarathon explains how to build that tolerance.

On a steep course it is easy to let fueling slip on the long climbs when your breathing is hard. Set a timer or use your aid-station rhythm to keep taking in calories on every climb, not just on the runnable flats, so you are not running the final Overlook pull on empty.

Sodium and fluid: tuned for the cool

Because late February near Auburn is cool, often in the 40s and 50s Fahrenheit, your sweat losses are lower than a hot summer race. So you can start with a more moderate sodium concentration around 300 to 500 mg per liter of fluid and adjust to your own sweat rate. The classic cold-weather mistake is under-drinking because you do not feel thirsty, and that quietly adds up over six-plus hours, so keep sipping on schedule even when it is chilly. Our guide on how much sodium per hour for ultra running helps you tune the number.

Dial in your own plan with our free ultra fueling calculator. Enter your weight, your goal time, and the expected conditions, and it gives you a carb, sodium, fluid, and caffeine prescription per hour built for the FOURmidable duration. Then go test it in training. Our full walkthrough on how to build an ultramarathon fueling plan ties it all together.

⏵ Free calculators for this race

Run your FOURmidable numbers with our free, no-signup tools, then let Summit Line tie them all to your real fitness and this exact course. Honestly, do the numbers before race week, not the night before.

See all free running tools →

⏵ Train for FOURmidable

Get a race-day plan dialed to YOUR fitness, this exact course profile, and your projected splits. Summit Line reads your actual training, builds a fueling and pacing plan around the FOURmidable climbs and cutoffs, and tracks how your gut and legs handle the vertical load. So race day is rehearsed, not guessed.

Get started free →See it on a real race

Train for the FOURmidable 50K

A steep, four-climb 50K rewards specific work: vertical strength, durable quads, and a rehearsed fueling plan. These free guides go deeper on the stuff that matters most for this course.

FOURmidable FAQ

How hard is FOURmidable?

FOURmidable 50K is one of the harder 50Ks in the Auburn and Cool area. It packs over 6,000 feet of climbing into about 31 miles across four named major climbs, almost all on unpaved trail with under a mile of road. The name comes from those four climbs: Cardiac Hill, K2 (also called Training Hill), Knickerbocker, and the final Overlook climb to the finish. Add the canyon descents to the American River, creek crossings, the cool and often wet or muddy February footing, and firm cutoffs near a 16:30 per mile pace, and you have a real foothills test, not a flat, fast 50K. It has hosted the USATF 50 km Trail Championships in past years, so the front of the field runs deep.

How much climbing is in the FOURmidable 50K?

The 50K carries over 6,000 feet of cumulative climbing, with Strava tracks usually reading around 5,947 feet, across roughly 31 miles. It is built around four major climbs instead of one giant ascent: Cardiac Hill early out of Overlook Park, K2 (the Training Hill) out toward No Hands Bridge, the climb back up to Knickerbocker, and the final Overlook climb to the finish. The gain comes in repeated steep canyon walls with matching descents to the river in between, so the course beats up your quads on the downhills about as much as it taxes your legs and lungs on the climbs.

How should I fuel for FOURmidable?

Fuel for a hard, steep, three to seven hour effort in cool conditions. Most runners target 60 to 90 grams of carbohydrate per hour, leaning toward the high end once your gut is trained, from a glucose plus fructose blend so you can absorb more. February near Auburn is cool, often in the 40s and 50s Fahrenheit, so your fluid and sodium needs are lower than a hot summer race, and a sodium concentration around 300 to 500 mg per liter of fluid is a reasonable starting point, adjusted to your own sweat. The bigger fueling risk in the cold is just forgetting to drink and eat, so set a timer and stay on your carbs through every climb. Our free ultra fueling calculator builds a carb, sodium, and fluid plan per hour for the expected duration and conditions.

What are the FOURmidable cutoffs?

The 50K has firm intermediate cutoffs at the major aid stations that work out to roughly a 16 to 16:47 per mile pace, with checkpoints including Knickerbocker, Cool, and No Hands before the final climb to the finish. The exact clock times shift a little year to year, so you cannot hike the front half casually. Build your pacing plan backward from the published checkpoint cutoffs with a buffer, because the repeated steep climbs and any mud will slow you more than a flat course would. Always confirm the current cutoff chart on the official FOURmidable race page before race day.

What is the weather like at FOURmidable in February?

Late February in the Auburn foothills is cool and can be wet. Daytime highs are usually in the upper 50s Fahrenheit with overnight lows around the low 40s, and February is one of the wetter months, so recent rain can leave the canyon trails muddy and slick. Plan for a cool start that may warm up into the afternoon, dress in layers you can shed, and pick grippy shoes if the trail reports show mud. The good news about the cool weather is that heat is rarely the limiter here. The course itself and the footing are.

Is FOURmidable a good first 50K, and is it on the Western States trail?

FOURmidable runs on sections of the historic Western States trail through the American River canyons, including the famous No Hands Bridge, and that is part of what makes it worth doing. It is doable as a first 50K for a well-prepared runner, but it is not a beginner-friendly flat course. The over 6,000 feet of climbing, the technical canyon descents, and the firm cutoffs mean you should show up with real vertical training and comfortable power hiking. If it is your first ultra at this distance, train the climbs and descents specifically and pace the early hills by effort.

This guide is for planning and training purposes and reflects publicly available information about the FOURmidable 50K. Race details, including the date, course, aid stations, and cutoffs, can change year to year. Always confirm the current specifics on the official FOURmidable race website before you train or travel.