Earth: Crevasse Rescue part 1
Posted by Joseph Anderson
Earth: Crevasse Rescue part 1
Tip of the Month Element: Earth (Rules and Hard Skills) Crevasse Rescue Part 1 (Arresting Fall to a 3:1)
2 climbers on one rope. One climber falls into a crevasse. Fallen climber’s rope does not cut deeply into snow.
The idea of setting up a pulley system in 1:1 Crevasse rescue can overwhelm many climbers. The important thing to remember is that as long as you’ve practiced these skills and are familiar with the hard rules you don’t need to think of it all at one time. Every step leads into the next. Here it goes:
Partner falls into a crevasse, you arrest the fall. The first step is the easiest because you have your climbing partner hanging on your harness while you’re digging your feet in.
Step 1: Transfer load to and anchor.
Rule 1: Always have a two point anchor. This is when you install your first anchor and transfer the load using your feet prussiks. Once you’ve relieved some of the tension by transferring most of the weight onto the first anchor point you need to be ready as the second anchor point. Install anchor point and tie an equalized anchor. Untie spare coils and clove hitch into the anchor.
Step 2: Check on your partner and prepare lip for a haul.
Rule 2: Close the system and make sure you are in it unless you know work area is safe. The best way to do this is to tie a figure eight on a bite with the end of the ropes. Clip this into yourself and then unclip from initial tie in. This creates a tie off point on either end of the rope in which you are still in after unclipping. Then extend the waist prussic with a sling if you have one. Walk down the rope with your ice axe while sliding your prussic and probing with axe. Once at the lip of crevasse check on your partner clean and pad the lip with a backpack or ski pole to prevent rope from cutting further into snow.
If you have deemed work area safe you can simply leave waist prussic which now becomes a tractor prussic for the future pulley system, leave a carabiner on it and clip a strand of rope through the biner. The rope strand is from the rope hanging off your harness. Then walk back up to anchor and pull rope through tractor biner until the rope is running from your hand, down to tractor prussic, up to clove hitch tie off on anchor and then finally back down to climber at the end of the rope.
Step 3: Increase Mechanical advantage.
Rule 3: Always introduce a new locker to the anchor when changing method of tie in. Currently you have a 2:1 mechanical advantage while pulling on your climbing partner.This means you are pulling half the weight of your partner plus the added friction of the rope going over the lip. This is too much and if you let go your partner would fall all the way back in. To increase the advantage so that you are only pulling a third you need the clove hitch to be simply running through the locker instead of locked up in a clove hitch. Here you introduce a new locker next to the clove hitch on the anchor. Pass a strand through the locker then lock it. Now while holding the rope that’s coming from the tractor you can undo the clove hitch. Now you have a 3:1 mechanical advantage (also known as Z pulley) and you can try pulling.
Step 4: Increase Mechanical advantage to a 6:1
To Be Continued…..