How To: Setting Top-Rope Anchors

Learn why, when alpine climbing, it is crucial to reinforce and thoroughly test a top-rope anchor to prevent fatal falls.
James Pierson James Pierson
October 08, 2015
How To: Setting Top-Rope Anchors
        With the weather starting to turn colder, this ice climbing incident from a while back caught my eye. The nature of the incident can be translated to any kind of top-roping situation and has some valuable lessons.

Back in December of 2014, two friends headed out near Alpental Ski Area in search of some ice to climb. They headed out towards Kiddie Cliff, and after a few hours of hiking and hunting for ice, the pair found a gully that looked promising. They made their way up until they finally came to a steep 40' tall flow of ice. There was a large cedar tree at the top of the flow, and the pair thought this would be a great place to set up a top-rope. Climber 1 scrambled up an easy gully on one side of the ice flow and traversed over to the tree to set up a top-rope using a "retired" climbing rope for the anchor. He tied one end of the anchor rope around the tree with a bowline and then tied a figure-8 on a bight on the other, then clipped the climbing rope to the anchor rope with a single locking carabiner. He then rigged his rappel on the climbing rope and descended to Climber 2.

After multiple laps by each climber up different variations of the ice flow, the pair decided it was time to start winding down. Climber 2 tied back in and climbed up as Climber 1 belayed. At the top of the ice, there was a short 3' vertical dirt step up to the 30-degree slope where the anchor tree was at. Normally, this would have been an easy mantle-style move to get up over the dirt step, but with soft snow at the base of the step and thick shrubbery on top, the Climber had difficulties. He decided to haul himself up over the lip by pulling down on the belay-end of the rope as his Belayer took up the slack. He moved slightly left to get in a better position, then pulled on the belay side of the rope and hoisted himself about a foot. The Belayer took up the slack and the climber slid his hands up the rope and hauled another few feet. As the climber slid his hands up the rope again, he noticed it was slack, saw the bushes in front of him shake, and then was suddenly falling through the air. He landed at the base of the climb and slid down the gully 35' until he finally came tight to Climber 1 at the belay. The fallen Climber was knocked unconscious, but came to about a minute later. At first, he was in a panic and didn't know what happened, but he soon started to remember events and quickly came to the frightening realization that he couldn't feel his legs.

Climber 1 used the bivy pad in his backpack and his two puffy jackets to insulate Climber 2, then told him that he was going for help. As dark quickly settled and and the moon rose, the fallen Climber struggled to stay warm. He knew he had a spinal injury but had to move a few times when his jacket almost blew away. After 3 hours of laying there, he heard the first sounds of the helicopter. It circled the valley, but then disappeared. Another hour passed before he started to hear voices. He called out, hoping to help the rescuers reach him more quickly. The rescue team approached cautiously, moving up and around, then rappelling down to the fallen climber from safety lines. They stabilized the fallen Climber while a paramedic was lowered from the helicopter that was now hovering above. The Climber was loaded onto a backboard, hoisted into the helicopter and flown to Harborview Medical Center. In the end, the climber had a mild concussion, but 6 broken ribs and 5 broken vertebrae, including a displacement of his lower spine which severed his spinal cord. He was operated on for 4 hours to fuse his spine back together with a series of titanium screws and rods. He is lucky to be alive, but will likely never walk again.

Lessons Learned:

While there are a handful of valuable lessons here (like always wear your helmet - it may have prevented this from being a fatal fall), I am going to focus on one major issue here: the anchor set up. Let's start from the ground up and examine the anchor this team used:

Main anchor point - According to the fallen climber, they used a "towering cedar" as their main anchor point. In most cases, using only one tree is acceptable, but it needs to not only be big and healthy, but it also needs to be examined to make sure it is well rooted. If you are going to use a tree for your anchor, it needs to really be holding on to the ground, at least 5" in diameter and healthy - no dead snags! Give that tree a push and make sure it doesn't topple over. When you attach your anchor material to the tree, it should be as low to the ground as possible to prevent torsion on the tree. Boulders are also often used for anchors. If you need to use a boulder, be sure to push and kick on that thing as hard as you can to be sure there is no way that it can move. Also watch out for sharp edges on boulders that can damage your anchor material. You can pad those areas with a foam pad or sticks if necessary. Lastly, make sure that there is no way that your anchor material can slip up over the top of the boulder.

Extension from the main anchor - The anchor material was not recovered after the accident, so there was no official documentation about how the anchor was constructed, but the two climbers described what they remember as best they can. In the case of our fallen climber, they used a "retired climbing rope" for their anchor, tied a bowline around the tree, then extended the rope down to the edge and tied a figure eight on a bight as their master-point.

  • The first problem here is using a "retired" rope. If a rope truly is retired then it should not be used for anything related to climbing ever again. If it wasn't fit to use as your main climbing rope, why would it suddenly be okay to use as an anchor? If you are going to be setting up a lot of top-ropes with natural anchors (trees and boulders) over the course of your climbing career, the best thing would be to buy a dedicated static rope. The dynamic properties of normal climbing rope allow it to rub back and forth against the rock as climbers weight and unweight the anchor. This rubbing wears down the rope and creates weaknesses over time. There is a minimal amount of stretch in a static rope so this rubbing is greatly diminished. Static ropes are also usually thicker and more durable than standard climbing ropes.
  • Secondly, using a simple bowline as a connection point to the tree is an issue. Bowlines have a tendency to loosen during cyclical loading, like the weighting and unweighting of an anchor during a session of top-roping. Bowlines should always be tied with enough tail left over to tie a double-overhand backup, similar to what you would do with the extra tail of your rewoven figure-8 at your harness. There is no mention of a backup in the climbers' reports.
  • Moving literally down the line, the next issue is having only a single rope extending to the master-point. With only the one line, all it takes is a sharp rock across a tight rope for the whole anchor to fail. There should always be at least two lines (often referred to as "legs") of your anchor coming down to your master-point. Most anchors using traditional protection (cams and/or nuts) will have three or more legs.
  • The last problem with the extension from the tree is at the master-point at the very end. By simply tying a figure-8 on a bight, there is only one strand of rope for the master carabiners to attach to. I'll come back to carabiners in a moment, but let's figure out a better master-point. Probably the most common and easiest knot to tie for a master-point is the Big Honkin' Knot (BHK). The BHK is basically double-bight overhand. Take a bight of rope from each of the legs of your anchor, put them together and tie a single overhand with both bights. This gives you a redundant master-point that is equalized between both legs of your anchor. Be sure to tie it so that it hangs over the edge far enough that your climbing rope won't rub against the rock. Any leftover rope should be tied off or clipped with a carabiner so it doesn't interfere with the master point or slip through.

Connecting the climbing rope to the anchor - In this incident, this is where the fallen climber initially thought the failure occurred. With only one locking carabiner connecting the rope to the anchor, the back-and-forth of the climbing and belaying, paired with moving the anchor side to side to climb on different sections of the ice could have loosened the gate of the carabiner. Since they didn't have the master-point properly extended, it moved back and forth in the dirt and snow, and then could have jammed open. It can't be proven that this is what happened, but this is exactly the type of situation that redundancy at your master carabiners would help prevent. Opposite and opposed locking carabiners have become industry standard for master-points in top-roping situations.

To summarize, in alpine climbing it is totally normal to use multiple pieces of protection to build your anchor, but then attach yourself to it with only one locking carabiner. But you are right there at the carabiner to make sure it stays locked and it does not have a rope moving through it for multiple hours, over and over again. You do a quick belay then move on to the next pitch and deconstruct the anchor.

The main lesson to learn here is that redundancy is crucial in a top-rope anchor. When you set up a top-rope anchor, you may not look at it again until the end of the day, so it has to be sound enough to endure hours of use, and if there is a failure in any part of the system, there needs to be redundancy to ensure there is not a complete failure, which is what happened in this case.