Desert RATS Trail Running Festival by UTMB
Desert RATS Trail Running Festival by UTMB – 100K
Fruita CO, Mack Exit, Hawkeye Trailhead
Race guide
Updated 19 July 2026
The Desert RATS Trail Running Festival by UTMB – 100K is a 100 km desert race starting from the Hawkeye Trailhead at the Mack Exit near Fruita, Colorado. It packs just 1,636 m of climbing with a high point of only 1,637 m, which makes it one of the flattest 100 km races on the UTMB calendar — but that runnability is precisely the challenge. There is nowhere to hide and no long climb to force a walk-break, so the course rewards runners who can hold a steady effort over rolling high-desert singletrack for the full distance. The route threads a network of named trails and overlooks — Rustler's, Pizza Overlook, Crossroads, Salt Creek, Rabbit Valley and the Western Rim — several of which are visited twice, giving the course a looped, out-and-return shape rather than a point-to-point line. With the start, both Rustler's stations, Rabbit Valley 1 and 2, Salt Creek 2 and the finish all serving as crew points, a well-drilled crew can make a real difference to your day.
The Course & Terrain
From the Hawkeye Trailhead the course sits in a tight altitude band between roughly 1,386 m and 1,637 m the entire way — the whole 100 km covers only about 250 m of vertical range, so this is high-desert running with constant small rollers rather than mountain climbs. The early miles run out past Rustler's 1 (10 km, 1,386 m) and Rustler's 2 (15.7 km, 1,386 m), both low points and both crew-accessible, before the ground tilts gently up to Pizza Overlook (22.1 km, 1,453 m) and Crossroads (28.4 km, 1,440 m). The middle of the race pushes out to Salt Creek 1 (40.2 km) and the turnaround territory of Rabbit Valley and the Western Rim, then retraces much of that ground: you will pass Western Rim (60.3 km, then again at 74.8 km), Rabbit Valley (52.4 km outbound, 82.6 km inbound) and Salt Creek (40.2 km outbound, 94.8 km inbound) twice. Knowing you will see these landmarks a second time helps with pacing — bank the terrain in your memory on the way out so the return legs feel familiar rather than endless.
Where the Race Is Won or Lost
Because the climbing is so evenly spread, the decisive section is not a single climb but the long exposed stretch from Rabbit Valley 1 (52.4 km) out to the Western Rim and back to Rabbit Valley 2 (82.6 km). This roughly 30 km loop over the rim is the most committing part of the course: it carries the tightest sequence of cut-offs (Western Rim 1 at 16:30, Western Rim 2 at 20:00, Rabbit Valley 2 at 21:15) and it is bracketed by a Water Drop at 72.1 km rather than a full aid station, so you must carry enough fluid to cover the gaps yourself. Runners who arrive at Rabbit Valley 1 already depleted tend to unravel on the rim, where the afternoon heat is at its worst and the trail keeps rolling without ever letting you settle. Conversely, reaching Rabbit Valley 2 with time in hand makes the closing run through Salt Creek 2 (94.8 km) to the finish very manageable, since the last 18 km trend gently downhill back toward the 1,427 m start elevation.
How to Pace & Fuel It
The clock is the real opponent here. The first hard gate is Rabbit Valley 1 at 15:00 (52.4 km), then Western Rim 1 at 16:30 (60.3 km), Western Rim 2 at 20:00 (74.8 km), Rabbit Valley 2 at 21:15 (82.6 km), Salt Creek 2 at midnight (94.8 km) and the finish at 01:00 on Sunday (100 km). The gap between Western Rim 1 and Western Rim 2 gives you three and a half hours to cover only about 14.5 km, which sounds generous but includes the exposed rim and the Water Drop-only resupply — plan to be self-sufficient on fluid and calories across that block. Use the crew points strategically: the start, both Rustler's stations, Rabbit Valley 1 and 2, and Salt Creek 2 all allow crew access, so stage cold drinks, salt and fresh bottles at Rabbit Valley in particular, since you hit it twice and it flanks the hardest section. Aid spacing is otherwise reasonable — rarely more than 12-15 km between stations — but the Water Drop at 72.1 km is the one place to double-check your carry before leaving the previous aid.
Conditions to Expect
This is a Colorado high-desert course run at around 1,400-1,600 m, so expect strong sun, minimal shade and wide temperature swings between the afternoon and the small hours. The cut-off structure has you finishing as late as 01:00 Sunday, meaning most of the field will run well into the night on the back half — pack a reliable headlamp and warmer layers for the post-midnight Salt Creek and finish sections even though the daytime is hot. Hydration and electrolytes are the defining variable. With the terrain runnable and the sun relentless, it is easy to push too hard early on the flat opening miles past Rustler's and pay for it on the Western Rim in the heat of the afternoon. Treat the first 40 km as controlled, drink to the heat rather than to thirst, and respect the Water Drop at 72.1 km as a genuine self-support point rather than a full aid station.
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Checkpoints & cut-offs
✓ Course data verified against the official source (2026-07-17) · official source
0 km · 1427 m · —
10 km · 1386 m · —
15.7 km · 1386 m · —
22.1 km · 1453 m · —
28.4 km · 1440 m · —
40.2 km · 1494 m · —
52.4 km · 1413 m · Sat 15:00
60.3 km · 1488 m · Sat 16:30
72.1 km · 1410 m · —
74.8 km · 1484 m · Sat 20:00
82.6 km · 1415 m · Sat 21:15
94.8 km · 1497 m · Sun 00:00
100 km · 1427 m · Sun 01:00
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