Boulder Skyline Traverse!! 1/19/20

I’m super proud of this one – 16.1 miles (17.4 miles if you count the return trip back down Mt. Sanitas after finishing) and 5,674 feet of elevation gain in 8 hours of hiking. The Boulder Skyline Traverse is a classic hike/trail run that traverses the five tall peaks in the Boulder foothills: South Boulder Peak, Bear Peak, Green Mountain, Flagstaff Mountain, Mount Sanitas.

I started this morning at 10:40am at the South Mesa trailhead and climbed up to South Boulder Peak via the Mesa Trail and Shadow Canyon Trail. I made the decision to do the hike from south to north specifically to get the worst climb of the day out of the way early (or so I thought) – the trail through Shadow Canyon essentially goes straight up, gaining 1,600 feet in 1.2 miles (an average grade of 27%), and is an absolute asskicker.

Eventually, you reach the top of Shadow Canyon and are standing on the saddle between S. Boulder and Bear Peaks.

Peak #1 – South Boulder Peak – 12:43pm

From there, I headed back down S. Boulder Peak, across the saddle, and up the short connector trail to the north side of Bear Peak’s summit. I scrambled up the boulders on the summit block, and checked Peak #2 off at 1:08pm.

I then scrambled back down the summit block and headed down the Bear Peak West Ridge trail – the first big descent of the day, losing 1,200 feet in just under 2 miles. The trail crosses a creek in Bear Canyon, where I had tentatively planned to refill my 2x 1-liter LifeWater bottles… but I wasn’t in too much trouble when I arrived to find it frozen solid.

Shortly after the creek, I took a hard left onto the Green-Bear trail and started a leisurely ascent up Green Mountain. After about 500 feet of gain, I turned right onto the Green Mountain West Ridge trail, which took me to the top of Peak #3 – Green Mountain at 3pm even.

Taken from the Green-Bear trail… check out how far I had come already! Bear Peak is to the left, S. Boulder Peak to the right.

From the summit of Green Mountain, I backtracked down the West Ridge trail and then turned right onto the Ranger Trail to descend down to Flagstaff Mountain. Descending the Ranger Trail took a hot second because it was steep and shadowy, meaning it was covered in ice. Before long, I was passing the Green Mountain Lodge and crossing Flagstaff Road for a short jaunt up the Ute Trail and to the summit of Flagstaff Mountain. The actual summit isn’t marked, and the highest point is described as a rock formation that resembles a molar… which I think I found? Peak #4 – Flagstaff Mountain at 4:07pm.

I was quickly running out of daylight (sunset was 5:04pm) and had the longest section between peaks to travel. I started down the Flagstaff Trail and turned onto the Viewpoint Trail at Panorama Point. After descending all the way back down into Boulder, I walked through Eben G. Fine Park where I refilled my water from a bubbler, put on my headlamp, and put on my rain jacket as an additional layer. After crossing through a tunnel, I hiked through Settler’s Park and down the hill to the Mount Sanitas Trailhead.

At this point, the sun had set and it was fully nighttime – I was hiking by the light of my headlamp. I started up the trail to the last peak, peak #5, Mount Sanitas via the Mount Sanitas Trail. And ya’ll, this was another absolute asskicker, for a few reasons: one, it’s objectively a steep hike as it gains 1,200 feet in 1.3 miles; two, it’s a steep hike when you’ve already hiked 15 miles; and three, I was doing this trail for the first time in the dark, by myself, with a headlamp. I dragged myself up that trail, getting lost a few times (thanks runner Kevin for leading me through a tricky section!), and seriously considering turning around as I was exhausted and knew that the descent would be just as rough.

But I couldn’t resist looking at my progress on the GPS, and, knowing I was SO CLOSE, decided to push on, and touched the sign at the summit with the loudest “fuck yeah!” howl I could muster at 7:08pm. I was so proud of myself, so happy I kept pressing onwards, and so in awe that I had just completed the traverse.

I stayed at the summit of Sanitas for a few minutes, enjoying the fantastic views of Boulder’s city lights, and then I headed back down the way I came. And it was a PAINFUL descent… and truthfully, it was more of a 1.3 mile controlled fall down the very steep and rocky trail. I arrived back down at the trailhead at 8pm, called a Lyft, and settled in for a 20 minute ride back to my car.

Things I’ll Do Different Next Time

I would like to hike the traverse again (maybe in the opposite direction), maybe with a group. I’m very happy with how the hike went, but there are a few things I’d change:

  • START EARLIER! 8am at the latest (from either end)
  • Bring water filtration – I passed a number of smaller streams along the way, but they weren’t moving fast enough for me to feel comfortable drinking it fresh
  • Remember my sunglasses! Whole lot of good they did me back in the car…
  • Attempt to hike Shadow Canyon with fewer breaks / a slower pace.
  • Consider ascending/descending Mt. Sanitas via the Lion’s Lair trail. The standard route is just painful.

Thanks for reading!

Author: Zach "Free Fall" Tucker

Long Distance Hiker, Traveler, Peakbagger, and AEA Stage Manager.