If a member of your rope team has fallen into a crevasse and can not ascend the rope or climb out on their own, then the rest of the team will probably need to haul them out. There are many possible ways to do that. We will focus primarily on three options that are relatively simple to learn and remember and will work in most cases, even if the rope has cut deeply into the lip of the crevasse during the fall.
3:1 Z-pulley system using a new strand of rope. This is also called a drop end.
6:1 drop loop system
If 2 or 3 rescuers are available to haul, this can be a simple and effective technique using minimal rope.
Steps (after transferring the load to the anchor, establishing contact, and preparing the edge):
Tie a knot in the free end of rope, clip a carabiner to it, and lower it to the fallen climber.
Bring the rope back to the anchor and redirect it through a pulley with progress capture.
Add a tractor (prusik or rope grab) to the rope and clip a pulley or carabiner to the tractor.
Redirect the free end of the rope through the pulley or carabiner. The free end should now be pulling away from the fallen climber.
This is a simplified demo of how to set up and use a 3:1 system by lowering a new strand of rope. It does not show the rope that the climber originally fell in on, but the system would be the same, just using the free end of the rope (rescue coils).
This system can also be set up using a prusik and pulley in place of the Microtraxion at the anchor and a prusik in place of the Tibloc as the tractor. See next section.
In the following video, a 3:1 is added to the original 3:1 system to make a 9:1
If you don't have a Microtraxion or similar ratcheting pulley, this method can be used with just a short prusik cord and a prusik-minding pulley.
A Grigri or ATC in guide mode could theoretically be used for this purpose as well, but the friction of those devices is substantial, so they are usually avoided in crevasse rescue except as a last resort.
If only 1 or 2 rescuers are available to haul, then more mechanical advantage may be needed. The 6:1 drop loop is a widely used option for that case. This generally provides enough mechanical advantage even for one hauler.
Steps:
Take the rope from the backside of the tie-in knot at the anchor, make a loop, clip a carabiner to the loop, and lower it to the fallen climber. Have them clip the carabiner to their belay loop and lock it.
With the free end of the rope coming back up from the fallen climber, bring it back to the anchor and redirect it through a pulley with progress capture.
Add a tractor (prusik or rope grab) to the rope and clip a pulley or carabiner to the tractor.
Redirect the free end of the rope through the pulley or carabiner. The free end should now be pulling away from the fallen climber.
Note: Steps 2-4 are identical to the 3:1 Z-pulley system above. This is just a 3:1 Z-pulley system built onto one side of the loop.
Watch this video for an overview of the 6:1 drop loop haul system. Before the beginning of this video, the rescuer had lowered a loop of rope with a carabiner to the fallen climber and had them clip it to their belay loop. To review how to prepare the lip and lower the loop of rope, see the second-to-last video in Glacier Travel and Crevasse Rescue 1 .