⏵ Course guide · San Juan Islands winter 100
The Orcas Island 100 sends its field around four 25-mile loops at Moran State Park, roughly 26,000 feet of climbing through old-growth forest, cold, wet, dark, and steep February conditions, and a required qualifier to even toe the line. I will walk you through the loop structure first, then give you a pacing and fueling plan built for a long winter island 100. There are free calculators along the way to dial in your own numbers.
These facts come from the official Rainshadow Running event page. Check the current year details, cutoffs, and aid stations before you commit. Race logistics change year to year.
The race runs four 25-mile loops out of Camp Moran at Moran State Park, roughly 26,000 feet of cumulative gain through old-growth forest with views of surrounding islands, mountains, and Puget Sound.
Since 2016, Orcas Island 100 has built a reputation as an old-school, laid-back, grassroots race. Because runners repeat the same 25-mile loop four times, aid station volunteers, crews, and staff get to know every runner across the day, and Rainshadow promises "we guarantee you will cry at the awards ceremony (at least once)."
A late-February date means real winter conditions: rain, snow, or sun, sometimes all in the same day. Rainshadow is direct that this is not for the faint of heart, and finishing means being ready for a full night, likely two, on cold, exposed island trail.
At the top of Mt Constitution sits a 53-foot stone tower with panoramic views of the Salish Sea. Runners can climb it on every loop to join the Tower Club, a special award for anyone who makes the climb all four times, a fun optional challenge layered onto an already demanding day.
With about 26,000 feet of gain across four repeated loops and a 36 hour clock gated by intermediate aid-station cutoffs, honest pacing on loop one matters more than it might seem.
Every 25-mile loop carries roughly 6,500 feet of gain, so an aggressive first loop borrows directly from the legs you need for loops three and four, deep into the cold and dark. A grade-adjusted pace target for the climbing gives you an honest number you can actually repeat four times.
Rainshadow enforces cutoffs at Camp Moran (mile 75), Mountain (mile 80), Cascade Lake (mile 90), and Constitution (mile 95) well before the overall 36-hour finish deadline. A vert-aware finish prediction built off your early loop splits is a better guide than the flat 36-hour number, since it is the intermediate checkpoints that will actually end a slow race.
⏵ Free tools to pace this course
A 36 hour clock and February weather that can swing from rain to snow to sun mean you are fueling for cold-weather ultra endurance, not just distance.
Aim for roughly 60 to 90 grams of carbohydrate per hour. Each of the four aid stations gets visited multiple times across the four loops, so use that frequency to keep intake steady rather than gambling on long, remote gaps.
Sodium in the 300 to 700 mg per liter range covers most runners, but the bigger factor at Orcas is temperature regulation: aid stations stock hot water and hot soup or broth specifically because cold, wet island conditions can sap you fast. Use those stops to warm up, not just refuel.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a cold, wet island February 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 four-loop climbing profile, and your projected splits. Summit Line reads your real training, builds a plan for repeated cold-weather mountain climbing, and rehearses your fueling so race day is something you execute, not guess at.
Rainshadow Running does not sugarcoat it: "this race is hard, beautiful, fun, rewarding, and really hard." Four 25-mile loops stack up to roughly 26,000 feet of cumulative climbing at Moran State Park, run in February weather that can swing from rainy to snowy to sunny across the same weekend. A 36 hour cutoff and a required qualifier (a 50-mile or 100K with 7,000+ feet of gain, or a prior 100-mile finish) keep the field experienced.
The race lists about 26,000 feet of cumulative elevation gain, and the same amount of loss, across the full 100 miles. That comes from four repetitions of the same 25-mile loop, roughly 6,500 feet of gain per lap, mostly on rugged single track through old-growth forest.
With a 36 hour cutoff, cold February weather, and roughly 26,000 feet of climbing, plan for a long day and at least one full night on trail. Aim for roughly 60 to 90 grams of carbohydrate per hour, and sodium in the 300 to 700 mg per liter range. Aid stations stock water, gels, Gnarly electrolyte drink, chips, fruit, chocolate, PB&J, soda, hot soup, and broth, plus rotating specialty items like quesadillas and sushi rolls at each station. Cold-weather fueling matters as much as carbs here: hot broth and soup at the aid stations are there for a reason. Build your numbers with the free ultra fueling calculator before race day.
The overall cutoff is 36 hours from the Friday 8:00 AM start, with the finish line closing at 8:00 PM the following Saturday. Rainshadow also runs intermediate cutoffs at the late-race aid stations (Camp Moran at mile 75 by 11:00 AM Saturday, Mountain at mile 80 by 12:45 PM, Cascade Lake at mile 90 by 4:00 PM, and Constitution at mile 95 by 6:15 PM), so a slow final loop can end your race before the overall 36 hours expires.
Entry requires a qualifier: an organized trail 50-mile or 100K with at least 7,000 feet of gain since January 1, 2021, or an organized trail 100-mile finish since the same date. All participants must also complete a day of volunteer trail work (6 to 8 hours) in the 12 months before race day, or make a donation to a trail organization in lieu of the work requirement.
No, and Rainshadow does not pitch it that way. The qualifier requirement alone (a 50-mile/100K with 7,000+ feet of gain, or a prior 100-mile finish) filters out first-time ultra runners by design. Between roughly 26,000 feet of climbing, February weather that can turn cold and wet, and the loop format's demand for real pacing discipline, this is a race for runners who already have serious trail ultra experience.
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<a href="https://runsummitline.com/guides/orcas-island-100">The Orcas Island 100 course guide</a>This guide is independent and for planning only. The course details, dates, cutoffs, and aid stations 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.