Four Pass Loop



26 miles

Elevation Gain

8000 ft

Route Type


Added by Logan Wenzler

If you want a humbling experience close to Aspen then look no further. This Four Pass Loop is not for the faint at heart, especially when the trail is non-existent due to snow cover. Read about this particular adventure to learn about WHAT NOT to do, and why two friends may have gotten in over their heads, but still came out okay while taking away valuable lessons learned.

Co-authored by Mike Hans, also present on this adventure.

Located just outside Aspen Colorado, the Maroon Bells-Snowmass Wilderness is beautiful with rocky peaks, dense forest, waterfalls, rivers, alpine lakes, and wide ranging wildlife.  The Four Pass Loop, starting at around 9,500 feet by Maroon Lake is about 26 miles long.  Traditionally, there are four passes on the loop ranging from 12,300 to 12,500 feet.  However, due to snow cover, the vast majority of the route was off trail with three climbs all reaching around 12,500 feet.  The route took us about 50 hours to complete. It’s worth noting that most of the trip guides recommend doing this as a four day three night trip due to the steep climbs and rough terrain.

A bit of a disclaimer:  My friend and I consider ourselves to be in relatively decent shape (and stupidly stubborn as this adventure illustrates).  I don't say this to brag, but to note that without this attribute we would not have finished the loop. We've done ultra marathons, CrossFit, extensive rucking and other endurance type events.  We have also done a few trips like this before in Yosemite, Big Sur, the Appalachians, and the White Mountains. I should also note that I’ve spent a lot of time in the field when I was in the Marines and my friend is well trained and experienced in survival and winter camping. With all that background, embarrassingly, this trip was not what we expected. Had we known the severity of the conditions we probably would not have done it at this time of year. To be perfectly blunt, we put our lives in a dangerous place, which we could have avoided with better preparation.


- No emergency beacon.

- Failure to tell friends/loved ones of our route and finish time. On any remote trip you absolutely need to share your planned route and provide an emergency number with specified time to call it if contact is not made.

-No poles or crampons.

-Failure to see how much snow there was, which changed our route drastically. Switchbacks were non-existent with all the snow, so we often found ourselves climbing near vertically, on all fours, up and down mountains.

-Jumping over streams with snow on top, not being able to see the actual bank.

-Sledding down peaks on packs/tarps because they were too steep.

The following attributes and actions were crucial for us to finish without any accidents:

-One of us had decent navigational skills including formal training and experience, while the other had survival skills and training that included shelter building, and "what to do in critical situations" knowledge.

-We were both trained in emergency first aid and were prepared with kits, tourniquet, and an emergency pack.

-GPS with route loaded, AllTrails route on cell phone, maps/compass.

-Above average fitness levels.

-Warm sleeping systems and warm clothing layers.

-GREAT WEATHER (sunny, no snow, no rain, minimal wind, no storms). For context it was roughly 60 by day and just below freezing at night.

-Plentiful water sources (this lightened our load which was crucial for the climbs).

We started the trip around 5:30 pm on a Friday in early June by Maroon Lake, so there was still a good amount of daylight to put a dent into the loop.  Here there was snow sporadically leading up to Crater Lake. We should have realized at this point, that since the rest of the route was higher in elevation, that were would be much more snow. We passed Crater Lake, and we were soon walking along the White River in the valley. At this point, we were either walking on medium sized rocks from rockslides that seemed to be everywhere or directly on snow. The trail was already covered. Using the GPS to follow the general direction of the route, we continued until close to sunset (we budgeted 45 minutes to setup camp and to get a fire going) where were found a small ridge with a relatively level patch of grass and rocks that was free from snow. We immediately dropped packs (and the dry brush we attached to them all along the way) and started setting up for the night. We used green pine tree branches to provide a little separation from the wet, soggy ground, built a small fire pit, ate some grub, changed out of wet clothes and socks, and went to sleep. During the night, there were some noises from what we thought were coyotes but they were not an immediate concern. Throughout the trip we kept our food in a Ursack bear bag, which we kept downwind from us at night. A bear bag or canister is required and an absolute must for this kind of trip.

Upon waking up to birds and daylight, we packed our gear, made sure the fire was out, and headed down to the river to filter water.  I brought a mini filter that came with a 16oz squeeze bag.  Although light, even filling up two 3L water bladders took longer than expected.  In the future, a bigger bag to hang and filter overnight, or in-line hose filtration system would have proven to be a huge time saver. We estimated that we spent close to three hours filtering water over the course of the trip. These were prime hiking hours that could have been better used. Not to mention, since the river was running underneath snow half the time, it would have kept our hands from being super cold while filtering.  We continued to slowly gain elevation and came to the first pass (or so we thought).  Here, instead of going west, we headed northwest and went up between Belleview Mountain and Maroon Peak.  Here we got our first real taste of vertical climbing in the snow, and were on all fours much of the time during this climb. Once we got to the top, we found the rocky part of Bellevue Mountain, had a bite, dried our soaking socks and boots, and scouted our way down.  The first part of the descent was loose rock, and so care was taken to not fall.  We zig-zagged down and kept our distance so that we wouldn’t knock debris into each other or risk falling into the other person. Once we descended the rocks, there was still a long descent to do in the snow. Here we had the bright idea to slide down on our packs. This saved some time, but the packs and our clothes got a bit wet. We should note that all our gear in the bags was kept in dry bags, which was critical for the nights. 

Before we began the descent we mutually decided to press on towards the next pass with the goal of making Snowmass Lake before sunset. Here we also set a 15:30 cut off time to begin our next pass ascent. Our reasoning was that if we were later than that we would have to sleep up on an exposed mountain, which was a bad idea. This was solid planning on our part, but something we didn’t stick to (more to come on that). The next few miles took far longer than we expected. The snow was deep and we would occasionally fall through to thigh or waist levels. We also fell behind on hydration, which sapped energy levels and slowed us down. About half way through this section of the trip we made our next major safety error. Coming to the top of a large and extremely steep descent (basically a cliff) we made the decision to climb down instead of trekking around. At one point my friend slipped in the snow and started sliding. Thankfully he managed to get a leg stuck into the snow to stop him from sliding too far and getting hurt. While this approach saved us at least an hour of additional hiking we could have easily gotten hurt. Now towards the bottom of the valley we had to look for a river crossing. We again took the approach of finding a place where the snow covered the river and then took a leap of faith. Each time we did this we alternated who went first, which was a small comfort but didn’t decrease the risk of falling through. After the river crossing we took a 45 minute hydration break, which recharged us for the section ahead.

By the time we made it to the start of the Trail Rider Pass ascent, it was already 16:30. We were an hour over our cut off time and should have setup camp. Wanting to make more progress though and hoping for a descent camp spot at higher elevation we began climbing. With the trail nowhere to be found we again found ourselves climbing on all fours, this time holding onto rocks, Poplar tree saplings, and anything else we could get our hands on. This was another risky climb that sapped us of our energy. As we continued climbing we started to realize that there would be no good camp spot. We began letting fatigue dictate our decision-making process as we climbed higher and so we decided to settle for the first fairly flat spot we could find. With sunset around the corner it started to cool quickly. We found a spot at around 11,500 feet that was exposed on the side of the mountain. From a survival training perspective this location broke just about every rule in the book. We were exposed to any potential storms, had no safe egress route and were precariously close to steep fall offs. Too exhausted and wet to keep going we quickly set out our tarps and ground pads on the snow, put on dry clothes, forced down a tiny bit of food, and passed out.

We woke up in the morning to a totally frozen surrounding including our boots, which hadn’t dried out a bit. After a quick cup of coffee and a small breakfast we made the decision to move quickly while the snow was still frozen over. We strapped our boots to the outside of our packs and wore our trail shoes. This ended up being a great decision as we were able to use the frozen snow and light weight shoes to make quick progress while our boots thawed out. The climb up Trail Rider pass would be our easiest climb although we again found ourselves having to go on all fours at times to avoid sliding down the steep slope with no visible switchbacks. We decided to sled down on one of the tarps because we couldn’t find any trail. This did save us a lot of time but it was hazardous given how fast we ended up going. We both learned is that depth perception is extremely difficult in the mountains, especially when everything is whitewashed with snow.

In good spirits and warmed by the sun we descended to Snowmass Lake using some bear tracks as a guide. This portion of the trip was wide open and so the route was fairly easy to figure out with the help of our GPS. At the lake we took another break to filter water and hydrate. My friend had been dealing with stomach issues going back to the previous day and had gotten dehydrated. While the break took a lot of time we managed to filter nine liters of water and drink a liter each before we started moving.  It is also important to note that one of these liters consisted of electrolytes. With nearly eight hours to go until sunset we knew we had to get over the final pass that day. Freshly hydrated and with a little bit of snack food in us we started trekking through the woods towards Buckskin Pass. This proved to be an incredibly difficult section to navigate with dense forest and no clearly visible route. We also both fell through the snow numerous times and had soaked feet. After several hours of this and a couple of precarious river crossings we arrived at the ascent. Just like with our past climbs there was no trail to be found and sheer walls ahead. We made the decision to climb vertically on all fours. This was our most dangerous climb and it covered snow, ice, rock and dirt faces for nearly 800 vertical feet. Because of the snow cover we didn’t really have a choice but this doesn’t negate how dangerous the climb was. At the top of the climb we found a wide-open area with a view of the pass ahead. For the next 1,000+ feet of climbing we set the strategy of take 20 steps and then take a short rest. The goal was to avoid burning out or “redlining”. We used this strategy until the last few hundred feet. From there the snow was often waist deep, slushy, and incredibly steep. Struggling on all fours we pushed on up the pass. It’s hard to quite capture the feeling of fatigue at this point but hopefully the following helps. We were so exhausted, soaked, and cold that we were reduced to the point of counting out 12 steps and then resting, often over a minute, before taking another 12 steps. 

It was 16:00 and we were excited to begin our descent knowing that all of the passes were behind us. The issue was that we couldn’t find a safe way down. The other side of the pass was steep, with snow overhanging it that further climbing ended up being required before there was an area safe enough to go over the edge. Because we could see rock cliffs farther down we decided that sliding was too dangerous. Thankfully the snow was deep enough that we could carefully cut a zig zag path down the face. If the snow had been hard packed we likely would have been stranded with no way to get down off the pass. This was another point where the danger of what we were doing really sunk in.

After our long, steep, and careful descent we began making our way towards Crater Lake (where the loop ends). We unfortunately got distracted and found ourselves between two rivers with no safe way to cross. This was a demoralizing point because had to turn around and climb back out until we found a river crossing. The crossing involved yet another leap across snow, which thankfully didn’t break. From here, the last four miles would prove uneventful as we eventually found the trail as the snow began thinning.

Knowing that we were home free and just had to hang on for a couple more hours we began reflecting, in detail, on the trip. We both expressed that this was the first time we had felt scared in a long time and that we were thankful to God for watching out for us. We got back to our car after just under 50 hours of backcountry trekking, completely wet, exhausted, and thankful that it was over.

The trip was a humbling experience where everything possible went right. We made a lot of dangerous decisions, sometimes because had to, and we were not properly prepared for contingencies. Four Pass Loop is something that everyone should experience, but learn from us and plan better (and maybe don’t go when there’s deep snow).

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