Ski Mountaineering Essentials: Crevasse Rescue Tips
Snow bridges are one of the biggest hazards of ski and snowboard mountaineering over glacial terrain. An innocent-looking swath of snow may hide the hazard lies beneath: a yawning crevasse of ice.
Snow bridges collapse without warning, but if you’re wearing a harness and are roped in (why aren’t you wearing a harness and roped in if you’re on a glacier?!), the essential gear in your pack will double as your emergency tools for a crevasse rescue.
You hope an emergency never happens, but you need to be prepared if it does. If you’re considering a ski or splitboard mountaineering trip, practice crevasse rescue scenarios in a class or with knowledgeable friends until you have it memorized. Implementing a crevasse rescue is a complex process that requires a systematic approach and quick thinking by all members of your party. In the meantime, here are some key pointers to remember when confronted with a crevasse emergency.
Falling into a Crevasse
If you’re suddenly and uncontrollably falling into crevasse, start yelling and alert your group as quickly and loudly as you can. If possible, make like a starfish and do anything you can to slow your fall.
Finding a Spot for an Anchor
As the rescuer, select a safe spot for you, your touring partners, and the anchor, ideally about 15 feet from the lip of the crevasse and close to the rope. Remain attached to the rope until your party has set up an anchor and successfully transferred the weight of the victim to the rope.
There are multiple types of anchors you can use to support the weight of hauling someone out of a crevasse, but you’ll likely rely on a T-slot anchor or an ice screw for a crevasse rescue. From a candy bar to a set of skis, you can use nearly anything as the foundation of your T-slot anchor – provided that the snow in front of your anchor point is firm and undisturbed. That might mean having to dig deep, past any sugary or faceted layers. Keep in mind, the smaller the object, the deeper you’ll have to dig. Study and practice building different types of anchors and know when one is more appropriate than the other.
Equalizing Your Anchor
If you’re unable to make a single-point T-slot anchor, you may need to employ the use of multiple anchor points, requiring you to distribute equal weight among the sling or rope. Equalizing a 2-point (or more) anchor maximizes its strength and reliability and is often tied off with a figure-eight knot on a bight at a master point on the sling/rope. That way, if one anchor fails, the second anchor can still be used. Keep in mind that the larger the angle between your anchor points, the greater the force on each anchor and the bigger the risk for ripping them out. To prevent a catastrophic anchor failure, check that the angle of each bight is no wider than the angular spread of your index and middle fingers.
Rigging a Z-Pulley
When a partner has fallen more than waist-deep into a crevasse – whether injured or not – a pulley system is the most efficient method to extract them. A pulley enables the rescuers to transfer the victim’s weight to the anchor and rig a system that reduces the amount of energy needed to pull him/her up. The most common pulley system for crevasse rescue is a Z-pulley that operates on a 3:1 mechanical advantage (ideal for touring groups of three or more people), meaning each tug on the rope is pulling up 1/3 of the weighted force. If it’s just you and your partner, consider building a 4:1 or 6:1 pulley system, which will offer more leverage for a solo rescue, although it requires more steps to assemble.
Over the Hump
Perhaps the hardest part of evacuating a victim from a crevasse, especially if they’re unconscious, is getting them over the lip. Before you transfer the weight of the load onto the anchor rope, probe to the edge of the crevasse and lay a set of ski poles parallel to the rim. As you haul the victim up, the ski poles pad the edge, prevent the rope from carving a rut into the snow and act as a ramp to pull your partner up and over the lip.
Above All, Stay Calm
Whether you’re being rescued or being the rescuer, take a deep breath and stay calm. Adrenaline will zap your energy quickly, and you may need to ration it, especially if you’ll need to evacuate an injured member off the mountain. And know that real-life crevasse rescue is different than textbook scenarios. You may have to improvise. Work quickly, but work smoothly. Panic doesn’t help anyone.
Practice may not make perfect, but it does improve your chances of a good outcome.