by Andy Selters
Before you start up, clip your pack to the rope below your prusiks or ascenders. This way, as you ascend, the pack's weight will actually help you raise your lower prusik or ascender by keeping tension on the rope, and as you climb the pack will be following you on a two-to-one “pulley.” You may have to keep the pack from snagging on small overhangs as you ascend. If the pack is heavy, it will be difficult or impossible to tie backup knots to your harness, so if the pack is big and your climb out is a long one, have a rope sent down to haul it up.
As you approach the top you'll probably find that the rope disappears into overhanging snow some frustratingly short and desperately steep distance below your goal, the surface. You can shove your prusiks up into the overhang, but to get over the top you'll have to employ any of a few different tricks.
First, you may be able to push away much of the overhang with your ax—carefully, though, with upward-directed pushes, because a sharp ice ax can cut a weighted climbing rope as if it were string. This will allow you to get your prusiks absolutely as far up the rope as possible. Then, the best option is for your buddies to set a prusik on the rope above the lip, and from it drop down a ladder of runners for you to haul up on. Or you might get enough height if you tie a figure-eight loop in the climbing rope for one foot to stand in; tie this as high as possible right below the lower prusik. For the final heave, if a partner can reach you with an outstretched ice ax to grab on to, it usually is easy then to haul onto the surface.
SURFACE MEMBER PROCEDURES
As mentioned in the introduction, extracting someone from a crevasse can be a fairly technical operation. Before getting into the procedures for surface members it's important to understand two of its primary elements: anchors on a glacier and the basis of pulley hauling systems.
ANCHORS
As we've said, most crevasse falls occur where a glacier is covered with some sort of soft snow. This is the highly varying medium that glacier travelers usually have to depend on for anchors.
The ubiquitous anchor for summer snow is the deadman or fluke, a simple metal plate with attachment cables. It works on the principle that a broad surface buried in the snow will resist a force because to move it you'll have to move all the snow in front of it. Two simple features on a snow fluke increase its reliability many fold. First, a fluke vertically bent so the convex side faces the load will accommodate pulls slightly oblique to the fluke's plane. Second, a fluke's cables should be swaged with the upper cable longer than the lower, so that a simultaneous pull on the two cables leaves the fluke tilted back at 30 to 40 degrees from perpendicular to the pull. With this cant a fluke resists any pressure to rise out of the snow. Set properly, a fluke with these features will actually move through the snow like an airfoil when loaded, deflecting itself down and burying itself deeper: A loop of cord attached to a fluke can make it easier to retrieve once buried (see fig. 3.4).
To place a fluke well, you must first evaluate the snow. In typical old summer snow, you can simply dig the necessary trench (as outlined in this section), but in particularly slushy snow or in never-melted new snow you'll first need to prepare the placement area.
When the snow is quite slushy, you usually just need to scrape away and dig down to the inevitable firmer snow below. But in unmelted, relatively low-density snow, you'll need to simulate age hardening. Essentially this means you dig, overturn and generally upset the snow, then stomp and repack the area. Then, before you dig in to set the fluke, wait five minutes for the broken crystals to rebond into a denser, firmer medium.
One must be wary of placing flukes if there's an icy layer not far under the surface, for such a layer can deflect a fluke upward. The layer can be either an old melt-freeze layer of some sort, or the ice surface of the glacier itself, but in either case you should use another type of anchor.
With the snow ready, you now set your fluke:
With the adz of your ax, dig a 1-foot-long trench perpendicular to the load and about a foot deep. Angle this trench about 30 to 40 degrees from perpendicular to the snow surface, the angle of the fluke to its upper cable.
With the pick of your ax, slice out a slot from the middle of the trench running toward the load. This slot is for the fluke's cables, and should be as deep as the original trench. This completes a T-shaped site.
Stretching the cables toward the load, set the fluke into the trench with the upper cable parallel to the snow surface. Set the fluke into the trench with a combination of pressing down on the fluke and pulling out on the cables.
Jerk the cable a couple of times and watch how the fluke reacts. If the fluke rides up when tugged, the cable slot is probably not deep enough, so it's putting a bend in the lower cable that lifts the fluke. Or if the fluke flaps against the trench wall rather than setting deeper, then the trench wall is not canted back enough, or you might have found an icy layer below. If the tugs set the fluke deeper, then you're in business.
Figure 3.4 Snow fluke
Figure 3.5 Properly placed fluke
In any case, the crustier the snow the more critical it is to set the fluke and its cables at the correct angle. With practice, placing a fluke takes but half a minute or less (see fig. 3.5).
The other well-known snow anchor is the picket, a simple post about 2.5 feet long. Pickets are normally reserved for firmer snow. Other than having a pointed tip for driving into very hard snow and an anchor hole at the top, there are few design considerations in a picket other than surface area. A variation on the traditional picket made out of T-shaped stock is the “firn tube,” basically a tubular picket. These can be driven into firmer snow more easily.
Pickets are simply driven into the snow, with a tilt backwards about 30 degrees from perpendicular to the load. Either hammer blows or boot stamps can pound one into fairly hard snow. Pickets are often the anchor of choice in very firm to hard snow such as old frozen snow or stiff windblown snow typical on the higher reaches of mountains. Even in firm conditions, however, it's more likely that a picket will lever out than that a well-placed fluke will fly out.
Michael Graber descending toward broken terrain on the west face of Yerupajá, Peru
Figure 3.6 Picket-deadman anchor
But there is a method for placing a very reliable picket−bury it sideways as a deadman (see fig. 3.6). As for a fluke, the procedure is as follows:
Prepare the snow if necessary, and then dig a trench as long as the picket, about a foot deep and perpendicular to the load. As you dig, undercut the trench toward the load.
From the center of the trench dig a trench as deep as the main one but perpendicular to it toward the load. If this trench is not as deep as the original, there will be an upward pull on the picket.
Girth-hitch a runner around the center of the picket, and then stamp the picket into the trench with the runner lying in the T trench. Finally, bury and stamp on everything except the tail of the runner:
In most snow conditions you will have a very strong anchor, but you can strengthen it further by driving a couple of ice axes or pickets immediately in front of it. Like any snow or ice anchor, this anchor is directional, only resisting a force perpendicular to the picket. An ice ax with a strong metal or composite shaft works equally well.
ANCHORS IN POOR SNOW CONDITIONS
In extreme conditions, when the snow is deeply slushy (as in low-elevation Alaska in June) or particularly dry (as in the Canadian Rockies in the fall and winter), it may be impossible to set a reliable fluke or picket. One anchor that might work is a couple of plunged ice axes equalized with people leaning on them. Remember; though, that the general theory of snow anchors is to resist a force with surface area. So when the snow is unconsolidated and weak, increase the surface area. For this reason improvised “dead men” can make the strongest anchors—for example, a pack, a pair of skis (ski poles are not strong enough), stuff sacks tightly filled with snow, or a shovel. These can be girth-hitched and thoroughly buried to give the best possible anchor in bad conditions.
> ICE SCREWS
When a thin layer of snow covers the icy ablation zone of a glacier, then any crevasse fall will have to be anchored in the ice. The quickest anchor in ice is an ice screw, and in fact an ice screw in solid blue ice is more reliable than any snow anchor Any of the tubular ice screws available work well in glacier ice, although longer models are much preferred for added strength in the often porous, softer ice of a glacier.
Just as snow anchors depend on snow quality, the most important aspect of a reliable ice screw is the quality of the ice. Glacier ice is wonderfully consistent and not brittle, but usually there's a superficial layer that you'll want to scrape away to get at the solid stuff underneath.
For the relatively moderate but prolonged loads of a rescue, it's crucial to tilt a screw back a bit away from the load—30 to 40 degrees from perpendicular to the load is best. However the eye of the screw should rest flush against the ice. Here's how to place an ice screw and accommodate both these criteria:
Chop a small ledge into the ice at the proper angle for the eye to rest against. By canting your ax pick away from the load at the same angle that the screw will be set in, you can then use the adz to chop exactly the ledge you need in just a few seconds. Often you can just use or enhance a small depression in the ice.
Place the screw so that the tip of the eye comes to rest as nearly as possible at the edge of the ledge, pointing toward the load.
When the screw is loaded, the carabiner you clip into the screw should then pull at the desired 30 to 40 degrees from perpendicular to the screw's axis (see fig. 3.7).
It's important to realize that pressure can cause ice to melt, even though the ice temperature remains at or slightly below the freezing point. Thus, during the prolonged loading of a rescue, ice screws can loosen dangerously. For this reason, when rescuing on a summer day with ice-screw anchors it's wise to add a backup anchor as described farther on in this section. On very warm days ice screws can slowly loosen even without being loaded; to alleviate this you can cover a screw with snow or ice chips and channel away any melt-water running over it.
Figure 3.7 Ice screw properly set for rescue anchor; note that the ice-ax head is at the proper angle to chop ledge so that the eye rests flush
BOLLARDS
A more tedious but very strong ice anchor is the bollard, a teardrop-shaped mushroom chopped out of the ice and looped with rope or webbing. Depending on the density of the ice, a mushroom 2 to 3 feet wide will be plenty strong; in fact, the main risk with a bollard is not the mushroom shearing off, but the rope or webbing rolling off. Therefore, it's the shape of a bollard that makes it safe or unsafe. Make sure that the load pulls downward at least slightly, and that the three sides of the mushroom that will bear the weight are well undercut.
To make a bollard:
Look for a relatively high spot where the load will naturally pull downward, then scrape away any superficial snow or ice that won't hold well.
Start by chopping the teardrop outline, gradually concentrating more on the three sides that will bear weight. Tubular adzes work best for this.
As your groove gets deep, small blows with the ax pick can fine-tune the undercut lip. Before trusting a bollard with someone's weight, loop the rope or webbing over it and see what protrusions if any might lift it off, and eliminate them. A trustworthy bollard distributes the load around a fairly even curve, without the anchor rope running over any high spots (see fig. 3.8).
Figure 3.8 Bollard
Even with practice it takes 10 to 20 minutes to chop a good bollard. Though a good one can be stronger than any ice screw and will not melt significantly, because of the time involved most people consider them as a backup to ice screws, or for cases when the need for ice anchors wasn't anticipated and screws are unavailable. One can also make a surprisingly strong bollard out of firn, although here the mushroom should be at least 6 feet wide and nearly a foot deep.
EQUALIZING AND BACKING UP ANCHORS
Other than a magnificent bollard, no anchor in ice or snow should be solely trusted for a rescue. There are three principal methods for coupling anchors, and which one to use depends on the anchor medium and the gear available.
Backing up.This method involves simply connecting a second anchor to the carabiner of the first one. The connection should have essentially no slack, so that if the first anchor fails or shifts, the weight transfers to the second anchor immediately without generating a shock load.
Figure 3.9a Backing up an anchor: measuring the spot to place the backup
Figure 3.9b Tensioned backup system
Measure the exact place to set the second anchor by stretching out a runner from the first anchor's carabiner behind the first anchor.
Set the second anchor so that its carabiner reaches just to the end of the new runner (see fig. 3.9a).
This simple system is fine for linking two flukes, because it's normal for the primary fluke to slip a bit once it's loaded, and start sharing the load with the backup.
Tensioned backup. When a primary anchor is already loaded, you can connect the backup with tension so that it shares the load. Do not use this until you are familiar with the tie-off.
Set a backup anchor “behind” the first.
Run webbing or climbing cord from the carabiner of the backup through a new carabiner on the primary and back toward the backup (see fig. 3.9b).
Pull hard on this runner creating tension between the backup and the load on the primary. Then clip it into the backup's carabiner.
While maintaining the tension, tie off the runner with a “slip hitch” tie-off, the same as for tying off a belay.
This is an excellent method to reinforce an anchor for hauling, and for linking one equalized pair with a second equalized pair
Equalizing. Distributing a load between a pair of anchors can more than double the reliability of the overall anchor Although webbing works fine, this is a good place to use a cordelette, a length (usually 20 to 25 feet) of 6-or 7-millimeter cord (or 5.5-millimeter soft weave Spectra). Many climbers carry a cordelette or two for lots of uses, usually tied in a loop with a double fisherman's knot, then bundled and clipped onto the harness. Two methods of equalizing anchors are presented here, the first quicker and more widely known, the second safer but slightly more involved.
For the first method:
Clip a long runner into both anchors, and make a twist in one of the two strands between them.
Clip a third (locking or doubled) carabiner through this twist and across the other strand (see fig. 3.10). When this third carabiner is loaded, the two anchors share the weight between them, even from a range of directions. Should one of the anchors fail the twist will preserve the connection to the other but the load will come onto the other after some movement, as a potentially severe shock load.
Figure 3.10 Equalizing anchors: method one
Figure 3.11a Equalizing anchors: method two; clip runners into two anchors
Figure 3.11b Equalizing anchors: method two; tie an overhand or figure-eight knot in a bight
For the second method:
Clip a cordelette into both anchors (see fig. 3.11).
Gather both strands of the cord and pull them directly toward the anticipated load, forming a bight.
Tie this bight into an overhand or figure-eight knot. Now you can clip the load to the resulting loop.
If the bight and knot are rigged properly, both anchors share the force equally. What makes this method safer is that if one of the anchors fails, that share of the load comes onto the other anchor immediately, preventing a shock loading. One concern with this system is that if the load changes direction most of the force shifts onto one anchor. But with most rescue loads you should be able to accurately predict the load's direction.
You can also use either method to equalize three or more anchors together; Clip one strand of the cordelette into each anchor, and gather the length between each anchor toward the load. Include the loop between the outermost anchors, an
d tie the bundle together. To equalize for a range of directions, just twist each strand between anchors into a loop and clip them all into the primary carabiner. You might have to add a runner extension to any distant anchors to have enough cord to equalize more than two anchors.
In any coupling arrangement, the connecting cord or webbing should be long enough to keep the angle between the anchors narrower than 90 degrees. If a short runner connects widely spread anchors, this angle broadens, and a sort of leverage geometrically increases the force on the anchors (see fig. 3.12). If a runner were tightly stretched between the anchor pair (at 180 degrees from the load), the force theoretically becomes infinite! For this reason anchors should be set slightly behind and slightly apart from one another. Flukes should be set a reasonable distance behind one another, to allow them to move some with added force.
THE ULTIMATE, PREFERRED ANCHOP SYSTEM
The most secure anchor system backs up one equalized anchor pair with another, using four anchors in all. This arrangement is especially recommended for hauling victims using snow anchors. After setting a primary anchor pair you use one of the backup methods described above −preferably the tensioned backup−to connect the equalizing carabiner of a second pair to the equalizing carabiner of the first.
