Americans Heather Jackson and Spencer Shellberg ran out the winners of the feature 100K races at the Desert RATS Trail Running Festival by UTMB over the weekend.
The event kicked off the North American UTMB World Series season as 1,800 runners converged on the high desert of southwestern Colorado to take on four distances – 10K, 21K, 50K, and 100K.
All had to navigate singletrack trails offering expansive desert vistas and dramatic clifftop views overlooking the Colorado River.
Shellberg a class apart
Jackson, the former top IRONMAN triathlete and now elite trail runner and gravel bike rider, had recently announced an incredible season schedule – one which she suggested “might break me”.
But it was her breaking her rivals as she led the women’s race from the outset and went on to cross the line in nine hours, 45 minutes and 12 seconds.

That was nearly seven minutes in front of Tay Calvett, with the pair well clear of third-placed Corinne Shalvoy.
In the men’s race it was local favourite Shellberg who triumphed in a time of 8:19:29 as he completely dominated.
That was over an hour in front of Michael Mitchell in 9:21:20 and Cody Cook in 9:24:25.
‘Big one on tap next’
Posting on Instagram, Jackson said: “Yayyyyy🤗 Beyond ecstatic to break the tape at @desertratstrailrunningfestival 100k today🤗💃🏼That was for one of my best friends from high school, @emmac24 … I thought about you and talked to you every second of every mile out there. Love you Ghetto❤️
“Thank you to my coach @slukenelson for getting me prepped for this, @seanwattiewatkins and Devon for crewing/supporting all day, and my incredible sponsors for their support.
“Thanks @desertratstrailrunningfestival 🤗🤗🤗 for a great race and to all the volunteers and everyone out there cheering all day🫶🏻 Congrats to our women’s field and all finishers today❤️ Time to recover ASAP😹😹😹 We got a big one on tap next…”
And that ‘big one’ is Cocodona 250 where among her rivals will be defending champion Rachel Entrekin and ultrarunning GOAT Courtney Dauwalter.

How the other races played out
The 50K saw Taylor Stack take the men’s win in 3:39:41, ahead of Justin Grunewald at 3:44:25 and Preston Cates in 4:02:23.
Sarah Carter claimed the women’s 50K in 4:09:45, followed by Claudia Tremps in 4:09:57 and Flannery Davis in 4:14:41.
Whit Blair dominated the 21K men’s race in 1:23:05, with Marty Andrie second in 1:27:30 and Brian Glassey third in 1:27:42. Janelle Lincks led the women in 1:36:48, followed by Mira Rai in 1:46:14 and Chloe Rylance in 1:46:31.
The 10K went to Chase Junell in 37:52, ahead of Kyle Wagener in 39:47 and Paul Brett in 42:43. Tabor Hemming won the women’s 10K in 0:40:38, with Hannah Bocksnick second in 0:45:12 and Sarah Hochtl third in 0:50:32.






















