Beaverhead Endurance Runs Course Guide

The ridgeline: high, exposed, and longer than it looks

The defining feature here is that you spend the day up on the divide. After the early climb off Bannock Pass you settle onto ridgeline that hangs around 8,500 to 10,000 feet for hours, with massive views and basically no shade. It looks runnable on a map, and a lot of it is, but the altitude makes every grade feel harder than the number says, and the rolling nature of a ridge means you are always climbing or descending, never quite cruising flat.

Pace this part by breathing and effort, not by your sea-level splits. The classic Beaverhead mistake is treating the early ridge like easy free miles because the grade is gentle, then arriving at the first hard cutoff already cooked. Up high, patient and steady beats fast and proud every time.

The scree: where you cannot just zone out

About 6 percent of the 100K (a bit more on the 55K) is boulder and scree, and that small fraction does more damage to your day than the percentage suggests. These are loose, rocky, ankle-testing sections up on the ridge where you have to actually pick your line and watch your feet. You will not set any speed records through them, and trying to is how people roll an ankle 40 miles from a road.

Get comfortable on technical, rocky footing before race day. Time on loose rock, quick feet, and a willingness to hike the gnarly bits instead of forcing a run will save your legs and your race. Trekking poles help a lot of runners on this kind of terrain, both up the climbs and for balance across the rough stuff.

The descent: more down than up, and it adds up

Here is the thing people underestimate. The 100K descends about 15,100 feet against roughly 12,700 of climbing, so the course tilts downhill overall, and the 55K tilts even harder. That extra descent is not a gift. Long, rocky, high-altitude downhill late in a 62 mile day quietly destroys quads, and the back half is where badly paced runners fall apart. If you bombed the early descents or never trained downhill at all, those closing miles toward Salmon turn into a slow, painful shuffle.

Practice controlled, runnable descending on rough ground before you show up. Being able to keep your legs turning over downhill late, when your quads are trashed and you are still way out there, is honestly what separates finishers from DNFs on this course.

Cutoffs and the partial night

The cutoffs are real and they come at you in the heat of the afternoon: Cutout near mile 38 by 2:30 PM, Goldstone near mile 46 by 5:30 PM, Janke Lake near mile 50.5 by 7:30 PM for the 100K. These are points you have to be moving through, not a buffer you bank for the finish, so build your plan backward from them with margin. Miss one and your day is over no matter how good you feel.

Because the 100K starts at 4:00 AM and runs long, you start in the dark and most mid-pack runners finish in it too. The race requires a headlamp at Janke Lake after 4:00 PM for a reason. Have your light and a backup, know how to fuel and move at night, and respect that an exposed high ridge gets cold and lonely after dark even on a July day.

Pace the ridge by grade and breathing, not the watch

Your flat-ground pace means nothing up at 9,000 feet on a rolling divide. What matters is grade-adjusted effort at altitude, so hold an output you can actually sustain up the climbs and hike the steep or loose pitches without feeling bad about it. The early ridge feels easy and that is the trap. Use a grade-adjusted pace to turn your real fitness into honest climbing and descending targets, then run inside them so you reach the afternoon cutoffs with something left.

Build a vert-aware finish prediction against the cutoffs

Do not guess your Beaverhead finish off a road time or even a flatter trail 100K. The 12,700 feet of climbing, the 15,100 of descent, the scree, and the thin air all add real time. A vert-aware finish prediction that accounts for this course gives you a realistic window and lets you work back into the mile 38, 46, and 50.5 cutoffs, so you actually know how much buffer you carry into each one instead of finding out the hard way.

Carbs: steady, trained, and easy to get down

For a long day like this, aim for roughly 60 to 90 grams of carbohydrate per hour, and only push the high end if your gut is trained for it. Altitude and sun both blunt your appetite and slow your stomach, so keep intake steady and simple instead of betting on big late doses you will not want to eat. Practice your exact race-day carb rate on long high or hot training runs so 80-plus grams an hour feels normal, not like an experiment you are running at mile 45.

Sodium and fluid: plan for the heat and the exposed gaps

Up on an exposed ridge in July, your sweat and sodium losses climb fast, so bias sodium toward the high end, often 500 to 700 milligrams per liter of fluid, and more if you run salty. Just as important, carry enough fluid to cover the long, shadeless stretches between aid stations rather than rationing to the next one and arriving wrung out. Weigh yourself before and after a hot long run to find your real sweat rate, then build the plan around your own number instead of a generic one.