A Solo Toprope System for Ice Climbing
There are many reasons why you might choose to climb solo. Finding reliable climbing partners can be hard, plus it allows you to practice over and over and doesn't require you to spend any of your time belaying. For these reason, and others, I chose to do most of my ice climbing via a solo toprope method. These systems can be relatively safe, as long as you use the right tools in the right ways. There are numerous methods and variations to setting up a self-belay system. Petzl has a lot of detailed info on this very subject. There are some basic standards and minimums for a safe setup. Here's how I set up mine:
The basic idea is with a self-belay system is to attach two separate ascenders to the rope, which allows you to easily climb upwards, but prevents you from falling in the event that you slip. It is essential to use more than one ascender for redundancy in case one device fails. Never assume any device is infallible, no matter how safe it may seem. Some devices are better than others, and some are really not acceptable for this application. The Petzl Tibloc, for example, is unacceptable. It requires the teeth to be set correctly before it is weighted. Failure to properly set the teeth may result in rope damage in the event of a fall. That is the absolute last thing you want your ascender to do while solo ice climbing. The Petzl Grigri can work, though I don't recommend it for two reasons: One is that the rope doesn't feed well through it, so you have to manually pull the rope through the device as you climb, which gets very annoying and tiring. The other reason is that if the rope becomes wet or icy (which it will), the Grigri has a harder time grabbing the rope and may not be able to stop a fall. I personally use a Petzl Ascension and a Petzl Croll. They both have excellent camming actions and are very difficult to open by accident. Be sure to follow all of the manufacturers instructions regarding whatever device you choose to use.
You'll also need some type of belay device to descend the rope if you get stuck or reach the top of the pitch. Really anything will do, as long as you're familiar and comfortable with the device. Though I recommend some type of auto blocking device such as a Petzl Grigri, Wild Country Revo, etc., as it provides a little extra security. But again, never assume your device is 100% safe, and always hold on to the rope while descending.
You'll need at least 3 large locking carabiners, one for each ascender and one for the belay device. Use whatever type of locker you are most familiar and comfortable with, I personally prefer auto-lockers, so that's what I use.
The rope(s) you use should be large-diameter, durable, and double-dry treated. For added security, you can use two separate ropes, connecting each ascender to a different rope, that way if one rope should fail, you don't fall to your death, which would be unfortunate. Static ropes are preferred for self-belay as they don't bounce when you weight them, which can weaken the rope over time.
This should go without saying, but the anchor to which you attach the rope should be absolutely bomber. Oftentimes you can find a rock or tree that is strong enough. Ice screws can also be used (three is typically sufficient), and they must be attached to the rope via an equalized anchor. Keep in mind that ice screws can melt out if the anchor is in direct sunlight, so cover the anchor with snow, tarp, jacket, etc. to keep this from happening. You can also use a combination of anchors, such as using two ice screws and a tree.
You should feel totally confident in your anchor before you weight it. It there is any doubt as to its strength, or even if something 'doesn't feel right' be sure to fix whatever needs to be fixed before you begin climbing.
You'll begin at the base of the route with your rope(s) connected. It is helpful to add some weight to the bottom end of the rope (suspended slightly off the ground) such as a water bottle, backpack, etc. to allow the ascenders to feed smoothly without having to manually pull it through. Choose one of your ascenders to be your primary ascender (I use the Petzl Croll). This will be your first line of defense against a fall. Since you generally don't want to shock load an ascender, you always want this device to be pulling up slightly on your harness. That way if you do fall, there's no slack in the system, and thus no way for you to gain momentum and increase the forces on your system. To do this: girth-hitch a runner/sling or a piece of cord to the top of the ascender to go around the back of your neck. As you climb, the ascender will be pulled up automatically. I use a 60cm dynex sling, though this piece does not need to be rated for anything strength-wise - it is only there to keep the ascender pulled up.
Your backup ascender will go below your primary one, there may be some slack on this piece, but it is only a backup in case the first device fails. Once both devices are connected to the rope, double check that all the teeth are engaged into the rope and that everything is working properly. Then triple check. Now you're ready to climb!
Your belay device should be clipped into one of your gear loops and should be readily accessible. I also like having a couple of ice screws and carabiners on my harness just in case something goes very wrong and I need to get off the rope. They can also be used to help you unweight the rope to remove the ascenders when you reach the top of the pitch.
Enough extra gear to build an anchor mid-pitch
Another thing you should always do in general, but especially with solo ice climbing, is let someone know exactly where you are, when you'll be back, and when they should call search and rescue. Don't take unnecessary risks, and don't climb beyond your limits. Know what you are capable of and what you are comfortable with. Roped-solo ice climbing can be very beneficial to help you develop your skills and practice moves, but it is not a substitute for a lack of climbing skills. Practice and refine your system thoroughly at home and you can have a safe and successful ice climbing experience!