The standard of crevasse rescue knowledge appears pretty low among Kiwi climbers, and instruction books tend to lack detail and at times teach impractical techniques. The following is what I have gleaned from people, books and my own experiences and tests. I am going to assume that you are familiar with basic crevasse rescue; if you are not, go through an instruction book and come back to this article afterwards.

The first section of this article details the exact process I go through in a standard single-rescuer crevasse rescue. The second section will expand on a few technical details and address a few myths. The third section asks, how important is proficiency in crevasse rescue?

1. How I effect a crevasse rescue

There are many effective and safe ways of getting a person out of a crevasse. This is my preferred method but there may be better methods.

1.1 Roping up

You will no doubt be familiar with the standard system of roping up for glacier travel, which involves coiling rope around the chest. This is sometimes referred to as “the Kiwi method”. However, there is presently a shift away from using our beloved chest coils. They are time consuming, pointless, uncomfortable and potentially dangerous. In the Kiwi setup, there are two attachments to the belay loop of the harness: one being a prusik coming from the rope running away from the climber; and the other being the knot that ties off the chest coils. The climber who is walking behind (and therefore more likely to have to hold a fall) slides their prusik forward (photo 1) so that the rope pulls through the waist, whereas the climber walking in front (and more likely to fall into a crevasse) slides their prusik back (photo 2) so that the rope pulls more equally on the chest and waist.

Experience and observation has left many believing most climbers are sloppy when it comes to sliding their prusik, and run the risk of being pulled forward from their chest when their partner falls because of a sloppy high attachment point (photo 3). Because of this, many climbers simply attach the rope to their harness via a carabiner to ensure the load is always below their centre of gravity, at the expense of the improvised chest harness that the coils are supposed to be. I clip with two carabiners into an overhand knot (or figure-8 or butterfly knot) tied 6m from the centre of my 60m rope and coil or spaghetti the remaining 24m of my end of the rope into my pack (photo 4). This is fast, comfortable and makes escaping the system simple.

1. Traditional Kiwi coils. The climber is second on the rope so has slid the prusik forward to ensure a low point of loading if the leading climber falls into a crevasse. Note the slack in the rope between the prusik and the coils.

2. The climber has slid the prusik back sufficiently so the load is shared between the prusik (running to the harness) and the coils. The climber is first on the rope and has the comfort and security of the full body harness system should they fall into a crevasse.

3. The climber has been sloppy and allowed their prusik to slide so far back that 100% of the load is going through the chest coils. This makes for a very uncomfortable crevasse fall. More importantly, if their partner falls into a crevasse, this climber is much more likely to fall forward onto their stomach and have great difficulty holding their partner’s fall.

4. This climber has stashed the extra rope in their pack and has clipped the rope to their harness. This ensures the point of loading is always low. Note that the knot chosen is an overhand (not a clove hitch) and that two opposing carabiners have been used.

1.2 Distance between climbers

The distance between two climbers on a rope is an important consideration. Simply put, you must have enough rope coiled around your chest or in your pack to effect a rescue. If you believe that you will be pulling your partner out of a crevasse using the loaded end of the rope then you certainly need to be reading the rest of this article. It is almost certain that you will have to 1) abseil to your partner on the remaining rope that you had coiled/in your pack and 2) then use this rope to pull them out, the reasons for which we will discuss a little later. To have enough rope to drop a line to your partner means the spacing between the two of you should be no more than 1/3 of the length of your rope. For example, if using a 60m rope, you need 20m of spare rope to be able to abseil to your partner 20m from you (with your partner having the other spare 20m of rope).

But hold on, we haven’t considered the knots in the system, let alone the rope needed to construct a standard z-pulley. Let’s imagine we only have a 50m rope and the climbers are 15m apart. That means they have 17.5m of spare rope each to abseil the 15m to their partner, which would only just be enough considering some rope is lost to knots. That leaves no rope to construct a z-pulley with. Indeed, if using a 50m rope, the climbers need to be closer to 10m apart, which for many is uncomfortably close. The message is that perhaps we should be using 60m ropes as standard and tying in no more than 15m apart.

Let’s now consider dropping a loop of rope from where you are standing at the anchor to your partner down in the crevasse, for an assisted hoist. In this case, the rope between you should be less than 1/5 the length of the rope. In the case of a 50m rope, this means you and your partner will be less than 10m apart. Hence, unless we are using a 60m rope or are able to walk close to the crevasse edge and away from our anchor, perhaps we should shelve the concept of the assisted hoist.

1.3 Holding a fall

People usually fall into slots when there is soft snow around, in which case the rope cuts into the crevasse lip, and the friction generally makes it easy to hold your partner by simply sitting down in the snow and digging your feet in. Tying knots (e.g., butterfly or overhand knots) in the rope between you and your partner makes it even easier and at times I have found these knots hold 100% of my partner’s weight. Do the knots in the rope impede rescue? As mentioned above, we usually don’t use the loaded rope in the rescue, and if the rope has cut into the crevasse lip then it can’t be used by the fallen climber to prusik out of the crevasse, so tying knots in the rope costs you little. It is the remaining rope taken as coils or in your pack that will be used for the rescue. The disadvantage of having knots in your rope is that it prevents you from simulclimbing (climbing on runners) when negotiating tricky sections of a glacier because the knots won’t pass through the runners. Hence, you may wish to use knots when walking on flat ground and untie them when you reach a steep section where you might wish to place runners.

1.4 Escaping the system

Provided I am not too close to the crevasse lip, I will inch forward until one of my knots is jammed in the lip. This allows me to remove my pack and construct a reasonable anchor (photo 5). I remove the coils from my pack and tie the rope to my anchor with a tied-off Italian hitch (photo 6). I can now inch forward and unclip from the system (photo 7). I don’t bother with intermediate ice axe anchors when escaping the system. Once I have escaped the system, I back up or improve my anchor if I am not totally satisfied with its strength.

5. The climber has got low and dug in their heels to hold the fall. The pack is then removed, an anchor constructed (reverse your car up to the edge of the crevasse making sure you have snow tyres or a 4WD), and the spare rope removed from the pack.

6. The climber attaches the rescue rope to the anchor with a tied-off Italian hitch. Note that the rope between the climber and anchor is as tight as possible.

1.5 Abseiling into the crevasse

It is very rare that you can perform a rescue without abseiling into the crevasse. Essentially, it is unlikely that you will be pulling your partner out of a crevasse using the loaded rope. Instead, you will be using the spare rope you had as chest coils or stashed in your pack, which I shall now refer to as "the rescue end of the rope". This is why it was important to have the spacing between climbers on the rope correct. You must have enough spare rope to effect a rescue, and the first part of the rescue involves abseiling to your partner on this rescue end of the rope. We need to abseil into the crevasse for a number of reasons:

• To prepare the lip of the crevasse so that the rescue end of the rope slides over a firm surface. It is not safe to do this without already being on abseil. For this reason alone you must abseil into the crevasse;
• To attach the rescue end of the rope to the victim, which they may not be able to do themselves;
• To steal the victim’s rescue equipment, pulleys, prusik and carabiners;
• To perform first aid, although there is little you can do in a crevasse;
• To make the victim warm;
• To adjust the way the victim is hanging to prevent suspension trauma.

It is technically safe to abseil off the tied-off Italian hitch but I have seen them lock up tight and even release their half hitches, so I prefer to tie a figure-8 and clip that to the anchor before I abseil (photo 8).

7. The climber inches slowly forward until the rope becomes tight to the anchor. The rescuer can unclip from the rope. Note that if a clove hitch had been used to tie into the rope instead of an overhand, the carabiners would be stuck in the tightened clove hitch.

8. Figure-8 clipped back to anchor to avoid abseiling off the tied-off Italian hitch. Abseil on the rope at the bottom of this photo.

1.6 Down in the crevasse

A big question for me is, do I prepare the lip on my way down or on the way back up? If the lip is a difficult one then you have no choice but to prepare the lip on the way down, otherwise you will not be able to prusik back out. This means leaving the victim unassisted for longer. The rescue end of the rope (the rope you are abseiling on) should be placed over some edge protection (e.g., ice axe shaft, ski pole or pack) and the lip cut back to a rounded rollover. This may take 30 minutes and necessitate dropping snow on the victim. Once I get to the victim, I pass the end of my abseil line through their coils (if they have some) and tie the end to their harness. Then I perform any first aid I can – this is very limited. I ensure they are in a sitting position and not hanging vertically, and I take all of their rescue gear. I then prusik back to the surface and leave my leg prusik on the rope.

9. The rescuer abseils into the crevasse on the end of the rope they had in their pack. Note the rescuer has a safety prusik on and is carrying a shovel and ice axe.

1.7 Constructing my rescue system

I like to move my focal point forward, away from the clutter of the anchor, so I tie another figure-8 1m forward of the anchor or further if I am short of rope (see photo 10). I pull in the slack on the line going to the victim and construct an autobloc (a prusik that locks the rope off when you let go). I always use a French prusik for the autobloc (photo 11). I place my second pulley here. I run the rope back to the leg prusik I left on the rope. I use my first pulley here (photo 12). My 3:1 pulley system is ready to go.

1.8 Powering up the system

If you are unable to haul the victim up using the 3:1 system, you can introduce another ‘z’ into the system to make a 9:1 system. I like to create another forward anchor point to keep the system tidy and efficient (photo 13). Another prusik is placed near the crevasse lip and the rope is passed through it and taken back toward the anchor (photo 14). You are now ready to pull on your 9:1. You will have plenty of prusiks and carabiners for this system because you have stolen all of the victim’s equipment. If you were properly spaced on your rope and you extend your focal point to within 2m of the lip, you will have plenty of rescue rope. Ideally you would move the pulley from the autobloc to this new ‘z’.

Once you have the victim on the surface, you have only just begun the rescue. They will need to be sheltered and you will need to go for help if you don’t have a communication device.

More mechanical advantage is not always the solution to a difficult rescue scenario. As we put more and more turns in our rescue rope, we introduce more and more friction and we can actually be making our system worse. I recently watched a rescuer struggle to extract a victim using a 6:1 system. They beefed the system up to 9:1 and still could barely move the victim. An hour of exhausting effort later, the rescuer reduced the system to a simple 2:1 and had the victim out within 5 minutes. It is essential that a rescue system is well constructed to reduce friction. This means knowing our systems and being suitably equipped. We shall cover this in detail later.

1.9 Getting the victim over the lip

This is usually the most difficult part of the rescue simply because we usually don’t prepare the lip adequately. If we have created a nice roll over or 45-degree ramp at the crevasse lip, we can simply continue hauling on our rescue system. If we have not invested the time earlier in the process then the victim gets stuck on the lip, and further pulling may fail the anchor or injure the victim. Sometimes a strong rescuer is able to manhandle the victim over the lip. Otherwise, the lip will have to be carefully excavated around the victim.

1.10 Summary

1. Hold the fall
2. Inch forward until knot is jammed in the edge
3. Remove pack
4. Create anchor with snowstake taken off pack
5. Take some coils off or remove a few metres of rope from pack
6. Attach rope to anchor with a tied-off Italian hitch (take up all the slack!)
7. Inch forward again until you are unweighted
8. Unclip from the rope and untie from your end of the rope
9. Improve your anchor or back it up
10. Tie a figure-8 just below the Italian hitch and clip to the anchor
11. Set up for an abseil and use a safety prusik
12. Take an ice axe, ice hammer, shovel and maybe even your pack to the crevasse lip
13. Assess the situation
14. Prepare the lip of the crevasse
15. Place the ice axe handle in the lip of the crevasse
16. Clip the leash of the axe into one of the knots in the loaded rope
17. Abseil to the victim
18. Give first aid, adjust the victim’s harness, fit a chest harness, steal their rescue gear, attach the victim to the end of the rope
19. Prusik out of the crevasse
20. Tie a new focal point forward of the anchor
21. Create an autobloc and remove snow from under the autobloc so it sits suspended
22. Set up a 3:1 pulley system
23. Make an effective seat next to the autobloc
24. Pull

I have completed and observed many simulated crevasse rescues in real crevasses and found most people are able to rescue a person of similar weight by pulling efficiently on a well-constructed 3:1 system. If the system is poorly constructed with a high-friction autobloc or the victim is larger than the rescuer, the 9:1 system is required.

Let’s move on from the process of extracting the victim to a few technical points that may help explain some of the elements of the process I have described above.

10. A new figure-8 knot is tied as the new anchor point. This avoids excessive clutter around the anchor. Note the overhand on the other rope is the knot the rescuer had used to tie into the rope for glacier travel. It now sits unused.

11. An autobloc is constructed on the new figure-8 anchor point, using a French prusik. Note that the loaded rope the climber was initially held on is not shown in the remaining photos.

2. Technical details

2.1 How to pull?

There are a few methods. The options include: standing and pulling hand-over-hand, tying the haul line to your harness and pulling by walking backwards, and the rowing approach. The problem with pulling hand-over-hand is that our arms are relatively weak, while the walking backward approach is usually badly restricted by friction on the snow surface. I have done some testing and the best pulling method by far takes a lesson from rowers. By sitting down and kicking out two big steps, we remove footing from the equation. Any standing method relies on secure footing, and poor footing can greatly limit our potential pulling power. Sitting down and pulling with straight arms, just like a rower, allows us to use the stronger muscles in our legs and core. Another advantage is that by avoiding hand-over-hand pulling, we can take on hand wraps, tie a hand loop or use a prusik to get the best possible grip on the rope. A further advantage is that our seat can be placed right next to our autobloc, putting us in a perfect position to monitor its effectiveness. I have never failed to rescue a victim using a 3:1 haul system and this pulling technique, provided I have at least one pulley in my system.

12. The rope is then taken back to the leg prusik the rescuer left attached after leaving the crevasse. Note the pulley has been placed on this prusik. See section 2.4 for a discussion on where to use your pulley if you have one.

2.2 Assisted hoists

Many instruction books teach assisted hoists, where both the victim and the rescuer are pulling. Assisted hoists are nice in theory but have limited applications. First, the victim is usually either well enough to prusik out of the crevasse or not well enough to help haul. There are very few medical reasons why a person would be sufficiently unwell to prusik but well enough to assist with hauling. Secondly, most assisted-hoist systems use a loop dropped all the way to the victim in the hole. This is often impractical because of the length of rope required. The most likely scenario where an assisted hoist might be useful is when the victim is unable to prusik because they don’t know how to. In this case, a simple 2:1 is an efficient way of getting them out if a strong rescuer can pull from the crevasse lip; pulling from the crevasse lip removes lip friction acting on the rope and lessens the amount of rope required. With a pulley and the victim taking half of their own weight, you will need to pull with about 25kg of force. The autobloc can be set and monitored by the victim and the rescuer can use a Bachman knot (a type of prusik knot that incorporates a carabiner as a handle) to assist in pulling the rope.

2.3 Suspension trauma

Humans are thought to have evolved from quadrupeds (four-legged animals). The power needed to pump blood around a horizontal body is much less than that for a vertical body, and when we began standing many years ago, our hearts could not cope. We have evolved a cunning method for returning blood back to our core that doesn’t require a bigger heart. Our leg veins are intertwined with our leg muscles and have a series of one-way valves that prevent blood falling back to our feet. When we are vertical, our blood is transported from our legs back to our core by the compression of our leg muscles pushing the blood up through the series of one-way valves, because the heart cannot produce enough pressure to do it alone.

Any time we remain vertical and motionless, we are putting ourselves at risk. The blood can’t get back to our core and we go into shock, resulting in loss of consciousness in as little as 5 minutes and as long as 20 minutes. This is why people faint in military parades. Once we hit the ground, the heart is able to pump the blood in our horizontal body back to the core and we recover instantly. However, if we can’t hit the ground, we remain unconscious, our airway can become compromised and death is possible. Even if our airway is intact, the shock of the old stale blood returning to our core can be fatal once we become horizontal. People have been killed by (1) being quickly placed horizontal after being vertically suspended for more than 10 minutes and (2) being suspended vertically and asphyxiating.

What does this have to do with crevasse rescue?

• If the victim is conscious and vertically trapped (e.g., in a tight crevasse) they need to consciously contract their leg muscles every 5 seconds to keep blood returning to their core and remain conscious.
• If the victim is unconscious and vertical, we need to protect their airway. If they have been vertical for 10 minutes, we must ensure we put them in a sitting position for 15 minutes before we put them in a horizontal position. If possible, we must immediately put them in a sitting position by pulling their harness leg loops toward their knees rather than letting the loops sit just below the buttocks.

2.4 Where to use your only pulley?

My testing and theoretical calculations agreed that a pulley will benefit you most if you place it as close as possible to where you are pulling fro. That is, place it at the first turn of the end of the rope you are pulling on. I found that placing the pulley at the autobloc in a standard 3:1 (z-pulley) system resulted in an actual mechanical advantage of 1.8:1. This increased to 2.1:1 when I placed the pulley at the turn immediately before where the rescuer pulls from.

2.5 Is it better to use a thin or fat rope for glacier travel?

This is a trade off. A thin rope imparts less beneficial friction on the crevasse lip when holding your partner’s fall. However, a thin rope creates less friction in your hauling system. An 8.4mm rope produced 5–10% less friction in all parts of my extraction system when compared with a 9.8mm rope. So, my advice is to use a thin rope but tie knots between you and your partner (unless you plan to place runners).

13. A new anchor point is created with another figure-8. Again, this helps to avoid excessive clutter and ensures ropes can run smoothly.

14. The rescuer has used a Tibloc (automatic prusik) to add an extra ‘z’ to the rescue system. They are now ready to haul on a 9:1 system.

2.6 What’s the best autobloc?

The most popular autoblocs are the prusik, Reverso and alpine clutch. In efficiency testing, the French prusik easily outperformed other prusik knots. The Reverso and alpine clutch are both less than 20% efficient, so a 3:1 system that uses either effectively becomes a 2:1 system at best.

Autobloc efficiency
Pro-traction  91%
Pulley and Tibloc 91% (note that this is prone to failure when horizontal)
Pulley and French prusik 85%
Pulley and classic prusik 80%
Carabiner and French prusik 51%
Reverso (or ATC Guide) 20%
Alpine clutch 12%

2.7 How much difference do all these details make?

Well, quite a bit. With a basic understanding and a basic selection of gear, you might produce a 3:1 system with an alpine clutch and no pulleys. There is nothing wrong with this system, it’s just inefficient. Friction reduces this system to a 1.5:1 system. If your partner and their pack weigh 90kg, then you need to pull with a force of 60kg. If the crevasse lip is soft, and it usually is, it is unlikely you will be able to pull your partner out.

With a little more understanding and the right equipment, you use a half rope, you and your partner both have pulleys (just one pulley is shown in photo 14) and you use a French prusik for your autobloc. Friction now only reduces your 3:1 system to a 2.7:1 system. Assuming a 90kg load in the crevasse, you will need to pull with a force of 33kg. Even if you have a difficult crevasse lip to negotiate, you still have a good chance of getting your partner out. If you are constructing more elaborate systems (with higher pulley ratios), then the effects of friction are even more pronounced.

2.8 Doubling up carabiners?

A number of books suggest using multiple carabiners for the rope to run around at each turn, to reduce friction where a pulley is not available. However, in my experiments, I found that using multiple carabiners actually increases friction.

Efficiency of rope running around one carabiner: 53%
Efficiency of rope running around two carabiners: 45%
Efficiency of rope running around three carabiners: 42%

So, don’t do it. You will waste carabiners and make your system less efficient.

3. How important is proficiency in crevasse rescue?

There are a lot more close calls than we hear about. Four friends of mine have had potentially serious crevasse falls in the last two years and a third mate had to extract a climber in another party on Mount Sealy. There have been numerous deaths in New Zealand and internationally from crevasse falls. Serious crevasse falls (as opposed to putting a foot through a hole) are not common, but they do happen and it is likely you will have one over a long climbing career. There are loads of climbs we can do without going onto glaciers but as soon as we enter crevassed terrain, we are putting our partner at risk if we do not have the required expertise. A climber who can’t rescue their mate is like a skier who wears a transceiver but doesn’t carry a shovel or probe. Ultimately, if you are not capable of pulling your partner out of a crevasse, then you are taking a huge risk and perhaps should not be on the glacier. Crevasse falls are way too common to be ignored.

Here is a summary of crevasse fall incidents involving my friends...

2007 Pequino Alpamayo, Bolivia The first climber on a rope of three fell through a bridge over a ‘bottomless’ crevasse and was held by the two climbers on the surface. The two on the surface pulled backwards and the victim used axes to climb 2m to the surface.

October 2007 An unroped ski-tourer fell through a thin lid on a crevasse at Frenchay Col, Franz Josef Glacier. He fell approx 18m into a v-shaped slot and stopped ‘softly’ with a large amount of falling debris. The pair of skiers had no harnesses, ropes or anchors with them. The companion returned to Centennial Hut alone to get help. Rescuers created an anchor, threw in a rope, harness and prusik. The victim prusiked out after three hours in the crevasse.

December 2008 The first climber on a rope of two fell into a crevasse in the Hooker Glacier icefall. The fallen climber was unable to move in the narrow crevasse and could not prusik out. He was extracted by his companion.

January 2009 A pair of climbers caught up with another party on the Metelille Glacier on Mount Sealy. One member of the leading pair had slipped off a narrow bridge. He was unable to prusik out and his partner did not know how to effect a crevasse rescue. The second party of two carried out the rescue.

November 2009 One member of a ski touring group on Hochstetter Dome was on a split board and was struggling to skin the final steep section. He stopped to put on crampons while the rest of the party moved ahead. He followed their tracks and fell through a thin lid over a ‘bottomless’ crevasse. He stopped on a 50cm-wide ledge 6m down. The rest of party noticed he was missing 20 minutes later. He was found, an anchor was constructed, a rope thrown down and the victim prusiked out.

How much practice is needed?

A lot of people say “I reckon I could cobble together a z-pulley system” when you ask them how their crevasse rescue skills are. Maybe this is Kiwi modesty or maybe they have just seen it in a book and know the ideas behind it; I don’t know. I think that the whole process – from roping up, to holding a fall, to getting your mate out of the crevasse – should be done from A to Z. Making a z-pulley in a hut or off a tree is good, but it only gives you part of the picture.

I believe there are few right and wrong answers in climbing, just better and worse ones. To walk up to Marcel Col not knowing how to get your partner out of a slot is not a wrong decision but it is probably a worse decision than spending that day learning/practising crevasse rescue in a filled crevasse near Pioneer Hut.

I had one couple on a course last summer who said learning crevasse rescue was their sole aim for the course. We spent three days on crevasse rescue. On the last day, I belayed the woman (50kg) as her partner (80kg) jumped into a big slot at the top of Turner Peak. She held the fall and did well to get him up to the lip with a 7:1 pulley system but couldn’t get him over the lip because she hadn’t cut enough snow away. This is the kind of practice climbers need to do.