Safety Equipment for Hiking Half Dome

The homemade “safety” equipment I saw on my most recent trip up the Half Dome Cables horrified me. I put “safety” in quotes, because in my opinion, many of these people are making themselves less safe, not safer, with these inadequate setups. Most of these people clearly have no rock climbing experience and do not understand basic climbing safety systems. In this article, I’m going to discuss:

Disclaimer: this is just my opinion. I’m not a guide, a manufacturer of safety equipment

What NOT to Use: The Death Clip

The most common setup I saw was what I call the Death Clip. This was people who bought two carabiners and a length of climbing webbing and clipped one carabiner to either their backpack strap or waist belt and the other went around the actual cable. There are so many problems with this setup that I barely know where to begin. As a rock climber, I would never trust that system and it gives me the chills seeing people use it on Half Dome, thinking they have somehow improved their safety.

On this last trip, I did not see anyone with a genuine climbing harness, but I have seen that on other trips where I climbed Half Dome by another route and was coming down The Cables. A genuine climbing harness is better, no doubt, but still potentially dangerous the way most people use it. A hardness and a simple tether are not designed for this use any more than it is designed for taking the place of the seat belt in your car. 

But isn’t it better than nothing?

Maybe or maybe not.

How could it possibly be worse than nothing?

Imagine systems like the ones I saw on Half Dome that to me appear very unlikely to hold a fall. So now the person has no *actual* safety equipment (so no risk reduction), but has two factors that now increase risk:

  1. He or she has a system to manage and clip and unclip, increasing the chance of getting distracted and taking a fall.
  2. He or she has a false sense of confidence. This might encourage her to pay less attention or push past her limits in false confidence that if she falls, this makeshift system will catch her. So her risk tolerance goes up, but she still has no safety gear.

It might conceivably make her safer only because she’s more relaxed… unless she’s read this article. In which case, she is going to want a better system

So will I surely die if I fall on one of these makeshift systems?

Not surely. You might, but there are some significant mitigating factors.

  • Half Dome is not very steep. It may seem so as a hiker, but when falling, you will absorb a lot of the fall energy through friction with the granite slab. It might be enough.
  • You might still even have a hand on the cable and be partly holding on, so that will reduce the forces more.
  • You might be bowling other people off the wall as you tumble down, which is bad for them, but is probably slowing you down
  • The stanchions are not in all that tight, so they have some sway and that would reduce the force some.

How much does all that reduce the force? I don’t know. And since I don’t know, I have to assume that you will exceed the design force for the equipment, and thus your body and that you could be looking at, say, a ruptured spleen if you get caught by a system like this. So if you’re asking for recommendations, I would every system I’ve ever personally seen hikers use on the Half Dome Cables is, to me, dangerous.

What Should You Use:  A Via Ferrata Kit

Whether you use a safety system is entirely up to you (more on that in a minute). If you do feel you want one, however, the only safety system that is actually approved for this usage is a via ferrata system that includes the necessary energy-absorbing components. Unless you have considerable expertise in rigging and know what you’re doing, if you want to use safety equipment on the Half Dome Cables, get something that is designed for that usage such as:

Note that sometimes these kits are out of stock on the manufacturer websites I link to, but they should be in stock at some retailer somewhere.

Petzl Scorpion via ferrata lanyard for Half Dome
Petzl Scorpion
Petzl Via Ferrata Kit for Half Dome
Petzl Via Ferrata Kit
BD Easy Rider via ferrata lanyard for Half Dome
BD Easy Rider
BD Iron Cruiser via ferrata lanyard for Half Dome
BD Iron Cruiser

Going Gearless: Do I Need Safety Equipment to Hike Half Dome?

This is one question I cannot answer for you. Personally, I have been up and down the Cables Route many times, with the cables both up and down and have never used any particular safety equipment aside from my hands and my brain. That said, I also have spent pretty much my entire life rock climbing, ice climbing, mountaineering and otherwise doing ill-advised things in the mountains. The approaches and descents from many, many climbing routes are much harder and more dangerous than the Half Dome Cables.

What is your risk tolerance? What is your fitness level?

The main thing to know what your comfort level is and what your fitness level is. If you are a framing carpenter and a runner and think a 10-mile run is trivial, you almost certainly have the fitness, grip strength and comfort with heights to be just fine on the Cables. If you get woozy looking off a bridge and you consider five flat miles a long walk, you probably shouldn’t attempt Half Dome at all. But if you do, you might be safer with some safety equipment. Do you get seizures when you’re tired or stressed out? Then some safety gear seems mandatory.

Are you guiding your child?

Yeah, that changes things. There are just too many considerations for anyone to tell you what you should or should not do. 

What do most people do?

Again, are you “most people?” No, you are just you. But nevertheless, here are a few observations:

  • At the end of the day, only a small percentage of Half Dome hikers have ever used and safety gear. The vast majority of them have gotten up and down just fine.
  • Every time I have been up there, I have seen at least one person frozen with fear, who probably would have had a much less stressful day with a little safety gear.
  • People do die on Half Dome. Many of these deaths are either directly or indirectly related to weather. In other words, in those cases they didn’t die because they lacked safety gear, but because they forged on even as storm clouds built. But for those who slipped on wet rock, safety gear and the knowledge required to use it correctly would likely have saved their lives.
  • It’s okay to turn around. Mountaineers have a saying: “The summit is optional. Basecamp is not.” If you’re super tired or you’re just not feeling it, do not go to the top. Don’t die from summititus.
  • The best safety gear you can bring with you is between your ears.

Safety Tips for Half Dome

  • First and foremost, use common sense. If you are new to outdoor sports, go with someone who has the experience to make good decisions. Remember, you do not need to go to the top. Repeat that. “I do not need to go to the top.” I have turned around on more outings in the mountains than I can count on three, perhaps four continents. The only regrets I have are the climbs where, against my better judgement, I did not turn around and almost died (usually weather related).
  • Gloves help. There are usually gloves at the bottom, but if you want to be sure of having gloves that aren’t three sizes too big, bring some. 
  • Don’t be afraid to take your time and catch your breath (but please let faster people by).
  • Never, ever start up the Cables if the sky looks threatening. If you see thunder clouds building, do not go up. The times I thought I should have turned around, but didn’t and almost died, all involved lightning.
  • Don’t be brought low by the Subdome. People focus so much on the Cables, that they don’t realize that the Subdome is quite steep and a longer climb than the Cables themselves. Last time I was up there, I saw several people retreat from the Subdome or be too exhausted after the Subdome to go to the top. If Half Dome is going to be a challenge for you in terms of fitness, rest in the shade, have something to eat and drink, and generally recharge a bit before the Subdome.
  • Set a turnaround time and stick to it. Despite what people think, it takes most people as much time to come down as to go up. For very tired people, it can take more. Decide what a safe turnaround time is. If you think you only have 10 hours of gas in your tank, then you have 5 hours to get to the top. If you are unwilling to hike in the dark and sunrise is at 6am and sunset is at 8pm, your turnaround time is 1pm. If you are not within spitting distance of the summit, turn around at your turnaround time.

Why a Via Ferrata System is Better

This is for the engineers in the crowd and probably more detail than most people want or need. But, if you are wondering why a simple tether is bad and a via ferrata system is better, here’s the semi-technical explanation.

There are three important parameters in any climbing safety system:

  • tensile strength
  • maximum force
  • energy absorption

Climbing ropes are not rated for tensile strength. You will never find a specification that says a climbing rope can hold 1750kg, because that is not an important number (plus technically it’s a mass, not a force, so meaningless in this context). Climbing ropes are rated for maximum force and indirectly for energy absorption (a fall rating).

The characteristics of a good safety system

So a climbing safety system must:

  • Be strong enough to hold the force put upon it. I just bought a new carabiner the other day. It’s rated for 24 kilonewtons. Roughly 5400 pounds. So it needs to be strong. But that is stronger than the human body, so…
  • Absorb energy. When you fall, the key thing is that you dissipate the energy. If you fall 50 feet and stop instantly because you are caught by a steel cable, that’s the same is hitting the ground (worse actually, because the load in concentrated). So climbing systems are designed to absorb energy.
  • Limit force on the body. Which brings us to the last category – the maximum force you can apply before you kill the climber. It’s easy to create a really strong rope that would nevertheless kill the climber because the stop is so abrupt that the force is very high. In the climbing world, this is called the “impact force.” The maximum impact force allowed by the UIAA for a certified climbing rope is 12KN, so half the rated force for the carabiner I just bought.

The characteristics of the systems I see on Half Dome

Now, think back to the systems I described that I see people using on Half Dome.

They Are Tied to a Backpack Strap

A backpack strap is not rated for any load except the one they expect you to carry in the backpack. The strap is usually sewn to the pack body with a single bar tack, so it can probably hold a maximum of 3KN, or roughly 674 pounds (a 22KN Black Diamond sling has 11 bar tacks, a Mammut 23KN sling has eight larger bar tacks). More importantly, that strap and stitching is undoubtedly stronger than the little plastic adjustment slider. Those typically aren’t rated at all, but if you hunt around, you can find suppliers who list the breaking strength and it’s not good news. A 5/8-inch buckle, typical of a backpack, has a breaking strength of about 53 pounds (aka 0.24KN) according to JAD Buckle and Best Buy Button and Buckle (supplier to Helly Hansen, Nike and other outdoor gear companies according to their About page). 

They use Standard Climbing Webbing

Let’s assume that your backpack is made with some superbuckle and it’s as strong as the bar tack and can hold 674 pounds. That sounds okay, right? Or, even better, you’ve upgraded to a genuine climbing harness rated to hold thousands of pounds. You attach this to the cable with a climbing sling and carabiner, each rated to 22KN, that is to say, roughly 5,000 pounds. Clearly, that’s safe, right?

No. This system as no built-in energy absorption. It’s possible the cables will have some give and the stanchions will sway and the attachment to the body will have some give and you will get the energy absorption you need. That’s possible, but you don’t know.

In testing, climbing slings that are rated to 22KN (almost 5,000 pounds) regularly break in falls of just 44 inches (111 cm) when loaded with 165 pounds (75kg)! If the stanchions don’t give and you pick up any speed at all, you will subject your body to a 22KN shock before the sling breaks. So it could stop your fall, but rupture your kidneys and break your back. And then what? Given where you are and how long the rescue will take, you’re just as dead.

Or it could just exceed the design load and break. If you have it clipped to your backpack, it will exceed the design load. The Death Clip system is one of the stupidest and most dangerous things I’ve ever seen. If you pick up any speed at all and stop quickly, you could exceed the max force your body can sustain or the maximum load the equipment can hold.

There are two basic problems in this scenario.

The first is that you have a static system. Of course there is some give in the stanchions, so give in your harness and your body. But your attachment system is basically a cable attached to a cable. There is no give in the situation. Essentially, compared to being caught by a climbing rope in a normal climbing situation, it is like the difference between a stuntwoman falling into an airbag and falling onto concrete. It’s not the length of the fall that matters, but the speed of deceleration. And in a static system (concrete or cable), the deceleration is rudely and violently abrupt. Your body and normal climbing gear is not designed for this.

The other problem is that these falls will have a very high fall factor. Let’s assume you plan to outsmart everyone and instead of climbing webbing, you attach yourself with climbing rope, which is designed to hold a fall. The problem is that climbing ropes are only designed to handle a “factor 2” fall and no higher, but your fall factor could be way higher. 

What Is Fall Factor?

Fall factor is a simple, but crucial concept. In brief, it is the ratio of the length of the fall to the length of your rope. So let’s say I have 100 feet of rope attached to a point 200 feet off the ground. If I climb up 10 feet and jump off, I take a 10-foot fall on a 100-foot rope. My fall factor is 0.1. That fall is going to be like falling into the airbag I mentioned above. Now let’s say I climb up to the attachment point and jump off. That’s a 100-foot fall on 100 feet of rope. That’s a fall factor of 1. And if I climb above the attachment point until the rope comes tight, that’s a 200-foot fall on a 100-foot rope, the mythical and feared factor 2 fall. 

The part that most climbers don’t understand is that the length of the fall is less important than the fall factor.  As a climber, I would far rather fall 40 feet with 200 feet of rope out (factor 0.5) than fall 20 feet with 10 feet of rope out (factor 2). The latter fall will be way more violent.

Now imagine that you have a 2-foot lanyard made of climbing webbing and you fall 20 feet down a cable before it catches on a stanchion. That is a factor 10 fall. No standard climbing rope or human body is made to sustain that.

Only one standard piece of outdoor equipment is made to sustain that load, namely the via ferrata systems, which are made to stretch and give and absorb the energy of a fall.

So if I am recommending equipment, the only equipment I can recommend in good conscience is equipment designed and certified by the UIAA for this usage, which is to say an actual via ferrata system. That is by far the safest option. Anything you use other than that will reduce your safety. So at that point, it’s just a question of your risk tolerance. In my case, I’m comfortable on Half Dome with no safety equipment. On the other hand, I’m also comfortable climbing Royal Arches with no safety equipment and that is a bona fide rock climb that most climbers bring the full kit for. What matters is what you are comfortable with, not what anyone else is comfortable with.