Julian Alps Trail Run by UTMB
Julian Alps Trail Run by UTMB – SKY TRAIL 50K
Žirovnica → Kranjska Gora
Race guide
Updated 18 July 2026
The Sky Trail 50K is the middle-distance mountain challenge at Julian Alps Trail Run by UTMB, a 50 km point-to-point line from Jezero Zavrsnica (637 m) to the finish in Kranjska Gora (811 m). With 2475 m of positive gain and a high point of 1843 m, it is a serious step up from the event's valley loops, delivering real high-mountain terrain in Slovenia's Julian Alps. This is a course built around one big early climb and a long, committing middle. From a low start it hauls you up onto the high ground before dropping deep into the valley and working back to Kranjska Gora. Runners drawn to sky-running-style terrain, sustained ascent and a genuine mountain crossing will find this the pick of the shorter distances here, but the front-loaded climbing demands respect and a patient early pace.
The course and terrain
The Sky Trail 50K runs from Jezero Zavrsnica (637 m, the lowest point on the course) to Kranjska Gora (811 m). It climbs almost immediately to Valvasorjev Dom Pod Stolom at 5.2 km (1179 m), then continues up to Sedlo Suha at 17.5 km (1438 m), with the 1843 m high point reached on the mountain ground beyond. From there the route plunges to Dovje at 34.1 km (709 m) before rolling through Gozd Martuljek at 45 km (752 m) and finishing at Kranjska Gora (811 m). The shape is clear from the numbers: a big, sustained ascent in the first third that gains well over 800 m in the opening 5.2 km alone and keeps climbing to the high point, followed by a long descent and a runnable valley finish. That means the bulk of the 2475 m of climb is concentrated early and high, on the exposed alpine terrain between Valvasorjev Dom and the high point, while the back half is about managing tired legs on the drop to Dovje and the final valley kilometres.
Where the race is decided
This race is decided in its first half, on the sustained climb from Jezero Zavrsnica (637 m) up past Valvasorjev Dom Pod Stolom (5.2 km, 1179 m) to Sedlo Suha (17.5 km, 1438 m) and the 1843 m high point above. Gaining over 800 m in the opening five kilometres is brutal if you attack it; the runners who settle into a sustainable power-hike from the gun and keep eating will crest the high ground with legs intact, while those who race the climb pay for it across the next thirty kilometres. The second decisive moment is the long descent to Dovje at 34.1 km (709 m). Dropping from the high point down to 709 m over rough mountain trail hammers the quads, and how you manage that descent dictates whether the closing valley legs through Gozd Martuljek (45 km, 752 m) to Kranjska Gora (811 m) are a controlled run-in or a survival shuffle. Descend within yourself and you can finish strong on the runnable final stretch.
Pacing and fuelling to the cut-offs
The published barriers are Sedlo Suha at 17.5 km (Fri 13:30), Dovje at 34.1 km (Fri 18:00) and the Kranjska Gora finish at 50 km (Fri 22:30). The first cut-off comes at the top of the big climb, so your early pacing has to balance patience with progress: hike the ascent efficiently but keep moving, because banking time is hardest here and easiest on the descent and valley that follow. Once past Dovje with margin, the runnable ground to the finish lets you convert good legs into time. Aid spacing is demanding through the mountains: 5.2 km to Valvasorjev Dom, then a long 12.3 km to Sedlo Suha, then 16.6 km to Dovje. Those two long high legs are where runners run dry, so leave Valvasorjev Dom and Sedlo Suha carrying enough fluid and carbohydrate to cover the gaps, especially across the exposed high point. Dovje and Gozd Martuljek are crew points, so plan a proper resupply and a food reset there before the final push to Kranjska Gora.
Conditions to expect
With a high point of 1843 m and long stretches on open mountain terrain, the Sky Trail 50K exposes you to genuine alpine conditions. The high ground between Valvasorjev Dom Pod Stolom and the summit can be windy, cold and quick to change even when the valleys are warm, and because much of the hard climbing is up high you may spend hours in that exposed zone. Carry and be ready to use a wind and rain layer, and do not judge the mountain by how it feels at the 637 m start. Underfoot, expect steep, rocky and at times technical sky-running terrain on the climb and the descent to Dovje, giving way to easier forest and valley trail on the run-in through Gozd Martuljek to Kranjska Gora. Confident, well-cushioned trail shoes with good grip are essential for the long drop off the high point. Check the mountain forecast closely, respect the potential for a big temperature swing between the valley floors and the 1843 m high point, and pace the early climb like the crux it is.
Race Julian Alps Trail Run by UTMB – SKY TRAIL 50K with Crux
Get the strategy, fuelling and crew plan dialled for this exact course — built from the real route, climbs and cut-offs. Your first race is free.
Plan this race — freeCourse profile
Checkpoints & cut-offs
✓ Course data verified against the official source (2026-07-17) · official source
0 km · 637 m · —
5.2 km · 1179 m · —
17.5 km · 1438 m · Fri 13:30
34.1 km · 709 m · Fri 18:00
45 km · 752 m · —
50 km · 811 m · Fri 22:30
More races
More UTMB World Series
More in Slovenia
Similar distance (50–100 km)
Racing Julian Alps Trail Run by UTMB – SKY TRAIL 50K?
Get a complete race strategy — pacing, fuelling, crew plan and the crux moments — built on this exact course.
Plan your race in Crux →Strava is your training. Crux is your races.