Race Details:
We are shaking things up for the 2027 race season, and we think you are going to love what's coming.
In June 2026, we introduced something completely different with Ultra Obscura in Sutton, Quebec. It was a new kind of ultramarathon that combined endurance, strategy, and a little bit of mystery. We had great feedback, and it started us thinking… Why stop at one race?
For 2027, we are taking the Obscura concept even further with a three-race series that will challenge runners to rethink how they race, how they compete, and just how far they are willing to push themselves.
No fixed distance. No need to commit in advance. Just you, the trails, and the question: How far can you go?
The Obscura race format combines the best elements of a traditional loop race and a timed ultra, with a twist that changes everything. It is designed for both crushers and new ultra runners.
Each race features three different stages that are repeated in order. Solo runners can now decide how many stages they want to complete; you do not have to decide your distance before the race starts. Teams still run the full course as described in the race rules.
Feeling great? Keep going. Having a tough day? Finish the stage you are on and call it a race. Want to see if you can push beyond your longest distance ever? Here's your chance. You can keep it to just a couple of stages, or go farther and break the 50km barrier for a full ultra. As long as you complete at least one stage, you will earn an official finish time. This is going to mean a lot more finishers as we try and push you a little farther. But here's where things get even more interesting…
In a traditional race, you know how far everyone is going. In an Obscura race, you don't.
That runner who just blew past you might be planning to go the full 24 hours, or maybe they are about to call it quits after the next loop. The person you have been chasing for hours might be your biggest competition, or they might be running a completely different race. You might reach the 100km mark and decide you want to go for a new record by smashing one more loop. You won't know who is really racing whom until the dust settles. We encourage good-natured deception to keep it interesting!
It is part endurance race, part strategy game, and part mystery. You will only be ranked against runners who complete the same number of stages as you, so there's always something to race for, no matter how far you decide to go.
That's what makes Obscura different. It's not just about getting to the finish line, it's about discovering what you are capable of along the way.
For 2027, the Obscura Series will feature three incredible events, each with its own character, terrain, and challenges.
June 19-20, 2027
The race that started the Obscura concept.
Ultra Obscura returns to Sutton, where runners first experienced this new format in 2026. With challenging trails, big climbs, and plenty of opportunities to test your limits, it's the perfect place to kick off the series.
We will be lifting the two-loop cap so that you can race beyond the original 85km, but you still have to finish in 24 hours.
August 28-29, 2027
A classic gets a shake-up.
Black Spur Ultra is joining the Obscura Series, bringing a fresh approach to one of our most established events. We are keeping the character and challenges that have made Black Spur a favourite but opening the door to new distances, new strategies, and even bigger goals.
Here's what's changing for 2027:
The traditional Black Spur distances aren't disappearing. We are building on the event's history and giving runners more ways to experience it.
September 25-26, 2027
Castle Alpine Trail Race is evolving into Castle Alpine Trail Ultra! Don't worry, we are still calling it CAT.
For 2027, CAT becomes a 24-hour ultramarathon, with runners tackling 28km route as many times as possible. Expect the same spectacular alpine scenery, tough climbs, and incredible atmosphere that have made CAT a favourite. Only now, you get to decide just how much mountain you want to take on.
We will have two sets of awards ceremonies: one on Saturday evening for the first finishers, then again on Sunday for the full ultra.
The CAT you know and love is still here; we have just given it a much bigger playground.
The finale of the series will happen at Castle Alpine Trail Ultra, along with the Four Horsemen. We will calculate your points based on the total number of loops completed at all three races. Anyone who finishes all three events with any number of loops gets an Obscura buckle. If you have the top number of loops, you are eligible for the podium where the top three women and men will be the Obscura champions.
They are not going anywhere!
Both challenges will continue in 2027. We will be updating the Sinister Triple points structure to accommodate the new Black Spur Ultra format while preserving the spirit of these challenges. We are also opening up the Four Horsemen to include any of our long-distance events.
One of the things we love most about ultrarunning is watching people discover that they are capable of more than they ever imagined. That's really what the Obscura Series is all about.
Maybe you have never run an ultra before, but you've always wondered if you could. Maybe you are a seasoned runner looking to break through a distance barrier. Or maybe you just love the idea of showing up on race day without knowing exactly how your adventure will unfold.
With Obscura, you don't have to commit to a distance months in advance. You just have to show up, start running, and see where the day takes you. One more loop. One more climb. One more chance to surprise yourself, because sometimes the biggest accomplishments happen when you decide not to stop.
Sign Up for the Obscura Series: Your race, your distance, your limits to discover.
Sinister Sports Inc.
Box 460 Bellevue, AB, T0K 0C0
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