FKT attempt: Pfiffner Traverse

Starting at 4 AM tomorrow morning I will attempt an unsupported fastest known time (FKT) on the Pfiffner Traverse, a 76-mile high route through Rocky Mountain National Park and the Indian Peaks and James Peak Wilderness Areas. This project has been on my radar for years, and the pieces have finally aligned to make a go of it.

The route

In Boulder there is disagreement over exactly what constitutes “the” Pfiffner Traverse. All variations use Milner Pass and Berthoud Pass as the termini, but beyond this parameter the interpretations range from a purist’s atop-the-Divide scramble to a more convenient mostly-trail ultra marathon course. The history of the route goes back to at least 1987 with Gerry Roach.

I’ll be following the Primary Route, which I’ve hiked and run in its entirety and in segments and about which I’ve written a guidebook. The Primary Route is the Goldilocks option: it generally stays high and close to the Continental Divide, but it deviates to avoid technical terrain, access better country, or keep a natural flow. In the tradition of backpacking high routes, this line is “just right.”

Steve at Paiute Lake in late-June

FKT history

In 2011 Mark Oveson completed a supported “fast Pfiffner” in 37:44. His route and the Primary Route overlap for many stretches, but have too many differences to be put in the same time category.

The only previous FKT attempt on the Primary Route was in 2018 by Sunny Stroeer, who did it in 2 days 6 hours and 41 minutes. It’s a strong time in the women’s unsupported category.

Goal time

I’m hoping to finish at least in 48 hours (B goal) but hopefully more like 36 hours (A goal). My thinking:

  • My time will be most strongly correlated with the route’s vertical gain (28,500 feet), not horizontal distance (76 miles). For very mountainous courses, routes, and trails, this is predictably the case.
  • My best comparison is UTMB, which had 33,300 vertical feet of gain and which in 2017 I finished in 24:44, meaning that every minute I climbed 22.4 vertical feet and descended 22.4 vertical feet, on average.
  • My fitness is not as high now, so I’m thinking that 20 vertical feet of gain per minute (a 10% reduction) is a better assumption when I’m on-trail, and that 13.3 vertical feet of gain per minute (two-thirds of my on-trail vertical speed) is a realistic assumption when I’m off-trail.
  • Using these assumptions, I get 28.6 hours.
  • Adjust for the higher altitude (+1 hour, or 47 seconds per mile), heavier pack (+1 hour), and longer duration (+1 hour), and then add cushion for weather delays (+ 2 hours) and sleep (+2 hours).
  • This gets me to 35.5 hours.


I’ll post my gear list in a separate post. When I leave the trailhead, my pack will weigh 9-10 pounds total, which has a surprising influence on pace and climbing ability.

The heaviest items:

  • Food (3 pounds)
  • Packed clothing (2 lbs)
  • Water (1.5 pounds when full),
  • My pack (1 lb), and,
  • Trekking poles (10 oz when not in use)

Recently I’ve gone for a few runs with my fully loaded pack, just so the weight and organization is not foreign to me on Tuesday morning.


Like many athletes, my 2020 racing plan was blown to bits by the virus. Last November I started training for the Colorado Marathon, which would have been my entry into the 2021 Boston Marathon, and I was on track to finish in the low-2:30’s. That race was cancelled, and so too were all my backup options, including both local (Colfax, REVEL) and distant (Utah Valley, Deadwood Mickelson).

A strained calf in June knocked me out for a few weeks, but otherwise my training has been consistent (60 miles per week, two workouts per week plus a long run) and my fitness has stayed high. When I threw down a 130-mile week with 24k vertical gain last month in Yosemite, it inspired me to commit to something competitive this year.

Why now?

Three factors are pointing to an August 4 start:

The full moon is today/August 3, and this extra ambient light will be hugely helpful at night, especially when trying to navigate off-trail.

The route is in-season. In late-June I attempted the single most difficult feature, the Northeast Gully, and turned around 10 feet from the top because I couldn’t get over the cornice. Six weeks later, it should no longer be a mountaineering objective.

Finally, my schedule has a gap. The summer is peak guiding season, but I’m in the middle of a 3-week lull. The timing isn’t perfect, but it’s really the only viable window.


The ideal scenario is to have a full moon, an in-season route, and bluebird skies. But typical of Colorado in August, it looks as if afternoon thunderstorms will be a factor.


I’ll be carrying an inReach and will send occasional messages along the way. Follow me here.

For more accurate track recording I will have my Suunto Ambit3 Peak GPS Watch (long-term review), which in this context is still my go-to choice because of it’s long-lasting battery. The Suunto 9 (my long-term review) is a nicer watch, but I find it less useful in its battery-saving modes.

Questions? Leave a comment.

Posted in on August 3, 2020


  1. Brandon Chase on August 3, 2020 at 9:53 am

    Fantastic – what an incredible adventure this will be. I’m glad that the Somewear now allows for a public tracking link – they didn’t offer this when I tested the device earlier this year and I suggested it to their reps after my review.

    Looking forward to following along – get after it!

  2. Ed C. on August 3, 2020 at 12:54 pm

    Just clicked on the ‘Follow me here’ link even though I knew you haven’t left yet. You realize that everyone knows where you live now as you had the device on.

    And they know you’ll be gone for a couple days…away from your house. While this community (backpacking community) is pretty small, there’s nefarious people in all of them. It’s never a good idea to release your whereabouts before a trip.

    The idea is kind of neat…we get to see where you are. But in practicality, it’s probably not the safest idea for your house and/or the family left behind. The only people that know when I’m going on travel is my wife and son and they know not to broadcast that I’m not around.

    • Andrew Skurka on August 3, 2020 at 1:18 pm

      Thanks for pointing that out. I was doing some testing around the neighborhood with the device.

      It’s odd that the device platform offers no option for deleting tracks published online.

  3. Ginny on August 3, 2020 at 1:39 pm

    Ian and I will be full-comfort backpacking in Dolly Sods and will pour one out for you….Hoping for minimal rain during your effort!

  4. Ben on August 3, 2020 at 3:02 pm

    “Goldilooks option”

    I like what you did there.

  5. Andy Fisher on August 3, 2020 at 3:25 pm

    Mr. S
    I love reading your travel adventures. You make the impossible seem a little more possible. Have you published your photographs from the JMT?

    Wishing you a great adventure!

  6. LinChee on August 3, 2020 at 5:12 pm

    Good Luck! Stay Safe! Go Get It!

  7. Karen Skurka on August 3, 2020 at 6:41 pm

    Good luck. Be safe. Have fun. We love you.
    Mom and Dad

  8. Mark Oveson on August 3, 2020 at 8:04 pm

    Good luck out there, and enjoy. Looking forward to seeing your progress.

    –The guy who you never mention re Pfiffner

  9. Mike Glavin on August 3, 2020 at 9:34 pm

    2 hours of sleep? During the day for warmth? During thunderstorms?

    I’m curious how and when you think you can catch 2 hrs w/no sleep gear.

    Best wishes and best of luck!

    If we raced, I estimate I would be 108 hours (3.5) days behind you, but I would have 38 hours more sleep and bottle of bourbon in me. So you would be the winner but it would also be a tie. Best wishes and best of luck!

    • Andrew Skurka on August 3, 2020 at 10:20 pm

      I think you just pull aside and lay on some pine needles, wrap up with the emergency blanket. As-needed basis, ideally done when I can’t be moving, like when off-trail in dark or during storms.

  10. Mike Glavin on August 3, 2020 at 9:40 pm

    It’s not how fast you can go
    The force goes into the flow
    If you pick up the beat
    You can forget about the heat
    More than just survival
    More than just a flash
    More than just a dotted line
    More than just a dash

    It’s a test of ultimate will
    The heartbreak climb uphill
    Got to pick up the pace
    If you want to stay in the race
    More than just blind ambition
    More than just simple greed
    More than just a finish line
    Must feed this burning need
    In the long run

    From first to last
    The peak is never passed
    Something always fires the light
    That gets in your eyes
    One moment’s high
    And glory rolls on by
    Like a streak of lightning
    That flashes and fades
    In the summer sky

    Your meters may overload
    You can rest at the side of the road
    You can miss a stride
    But nobody gets a free ride
    More than high performance
    More than just a spark
    More than just the bottom line
    Or a lucky shot in the dark
    In the long run

    You can do a lot in a lifetime
    If you don’t burn out too fast
    You can make the most of the distance
    First you need endurance
    First you’ve got to last

    -Neil Peart (1952-2020)

  11. Katherine on August 3, 2020 at 10:09 pm

    We’ll be following along. I am confident that you’ll make your A goal. Good luck and have fun!

  12. Bill Wright on August 4, 2020 at 11:38 am

    Hi Andrew,

    Good luck on this grand adventure! I hope it goes well.

    I’m quite disappointed, though, that there is no mention here of Mark Oveson, the guy who invented this route (though your version has relatively minor, but very nice improvements) and has set the FKT at 37h44m, which he did in August of 2011. It appeared in Backpacker Magazine in an article about classic mountain traverses. Not surprisingly, it was listed as the hardest, with a rating of 10 out of 10. I know you and I know what a great job you do on research. I know you were aware of this. You are more famous than Mark and most people will eventually know this traverse because of you than because of him, but to excise him from the history isn’t right. It’s almost like theft. You are (or should be) better than that.

    In full disclosure, Mark is my best friend and I accompanied him on the second half of his FKT. His brilliant, moving account of his creation (yes, his creation) is here: (yes, Peter misspelled Mark’s last name).

    Bill Wright

    • Andrew Skurka on August 6, 2020 at 11:09 am

      It was certainly not my intention to slight Mark, and I’ll update the text to reflect that.

      My understanding is that the Pfiffner Traverse goes back much longer than 2011. Gerry Roach did a version of the route in 1987 and included it in his IPWA guidebook,

      • Mark Oveson on August 6, 2020 at 4:20 pm

        Thanks for making this change, Andrew. Very much appreciated.

        Congratulations on your successful Pfiffner! That’s a huge undertaking and an outstanding effort.

        You are correct that Pfiffner Traverse history goes back well before 2011. Gerry Roach (not Roche) named the concept and completed the first incarnation of it in 1987. He was my inspiration.

        Although my route differed from Gerry’s much more than yours does from mine, I spoke to him personally after my successful 2011 attempt, and I made it clear in my own TR that the route was his vision and I stood squarely on his shoulders.

        • Andrew Skurka on August 6, 2020 at 4:51 pm

          As you very well know, it was a big effort, thanks. Would be interesting to compare notes sometime about our respective experiences.

          Thanks also for catching the Roach misspelling. I’m usually better about such things, but brain fog has been a day-long theme. It’s almost like I’m still at 13k.

          • Mark Oveson on August 6, 2020 at 5:40 pm

            I’d love to do that. Yes, let’s catch up when you’re fully recovered.

            Again, thanks for making this right. You are the man.

        • Colby Renfro on August 6, 2020 at 4:58 pm

          Thanks Andrew for updating it, we were following along too and comparing the route to Mark’s and looking into the variations it was a fascinating learning experience as I’m wanting to do a similar route as a backpacking trip in the future. As a backpacking trip there will be different objectives entirely so it has been fun to research the different variations as we plan to do a variation of the Sunny/Skurka and Oveson routes.

          I know you did mention Gerry/Mark/Pfifner in other places on this site, but I think it was the right move to recognize that another male had made an attempt on a similar route (& obviously Sunny who crushed this as well)

          And finally: congrats on the route! I’m new to your work and website but have already found what you share to be both entertaining and educational.

  13. Cordis on August 4, 2020 at 12:28 pm

    Good luck and have fun! Weather is looking great.

    I have to say though, you are definitely wrongly omitting Mark from the history of this route (creation and accomplishments) when he is, without question, the first person to complete in a single push Milner to Berthoud. I get that you’ve put a lot into the route as well, but credit where credit is due, Mark put together the first version of this as a one-push thing and laid the foundation that we all grown to love.

  14. Abby on August 4, 2020 at 12:53 pm

    Hey Andrew,

    There’s a deep range of history on this route from over the years beyond the line you have put together. I would be cautious before making a statement like ‘first known attempt’ when many have come before you. Namely, Mark Oveson who has been a mentor to Cordis and I since we first started making Pfiffner attempts in 2016.

    Mark was the first one-push finisher and spent years on this project himself. I’d like to argue Mark established the “Primary Line” on this, and we’re all just making variations on his. 😉

    Kobe Bryant said something about Michael Jordan, ‘you don’t get me without him.’ To me, the beauty of FKTs lies in a shared history on these special routes and that we all push each other, even when we attempt by ourselves. The history is simply too deep here to call it a first known attempt. I know you are referring to your specific preferences on the route when you say this, but I’ve got to point credit to where credit is due.

    Good luck out there and have fun!

  15. Brent on August 5, 2020 at 10:13 am

    Yes! Great choice. I think Mark Oveson did a similar route years ago. Wonder if he dialed the “Goldilocks” bypasses of divide proper in the same manner.

    • Andrew Skurka on August 6, 2020 at 10:57 am

      To Mark’s credit, it’s difficult to get it truly “right” when you’re the first. I have found this with every route that I have put together — what seems to be the best line on paper is not the best line in reality. To find that one, you really have to do the route forwards and backwards, in segments and in its entirety, and in multiple seasons.

      My personal take is that Mark’s route falls in an unfortunately middle ground of sometimes being overly pure (like hitting many of the peaks in Rocky) but then other times being too convenient (like bypassing Paiute Pass and Northeast Gully).

  16. PS on August 5, 2020 at 9:44 pm

    Congratulations Andrew! Was fun following along.

  17. Dave Weyrick on August 5, 2020 at 9:53 pm

    Congratulations Andrew! Looking forward to the story after you get lots of well deserved rest.

  18. macy on August 6, 2020 at 10:07 am

    Congratulations, Andrew. Can’t wait to read the debrief.

  19. Adrian on August 6, 2020 at 10:25 am

    Do you remember when you wrote this?

    Jokes aside, great effort! I attempted this in late September last year, but bailed over Bucchanan as I would not make it over and down to Arapaho Creek before the sun failed. Those down climbs were sketchy enough in daylight when I had previewed it the week before. I’ve wanted to try it again, but I’ve moved away from Lyons, CO.

    • Andrew Skurka on August 6, 2020 at 10:52 am

      I do remember writing that, and its guidance is equally well informed today as it was then!

      For a FKT one crux does seem to be getting to Arapaho Creek by nightfall. The remainder of the route is more do-able in the dark, especially with a full moon.

  20. Al son of Sven on August 9, 2020 at 6:31 pm

    Destroy it! I hope you have a good time doing it!

  21. Ed C. on October 2, 2020 at 8:45 am

    For those of us that couldn’t follow along…what was the results? Did you ever do a write up?

    • Andrew Skurka on October 3, 2020 at 6:29 am

      I finished in a little bit less than 39 hours. I have not done a ride up yet, but plan to. It’s been tough to get anything done with the guiding season.

      • Jacob Kosker on December 2, 2020 at 10:16 am

        Still waiting anxiously for that write-up! Wondering about so many parts of this experiment like your thoughts on the gear you used. What vest did you take? Anything you didn’t bring but wish you had? Will you attempt another light and fast effort like this again? I am considering this style of adventure as an alternative to ultras.

        • Andrew Skurka on December 2, 2020 at 10:37 am

          I’ll try to get to it. As soon as I finished it, I was straight into a really intense stretch of guiding, and as soon as that ended I needed to pivot to 2021!

          You should DEFINITELY consider trips like an alternatives to ultra races. You can do better routes, on your time frame, and at less cost. There’s no support or race atmosphere, but I don’t think those losses are enough to tip the argument.

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