Incidents:Death in Salamander Canyon
|Death in Salamander Canyon|
|Body movement problem||No|
Joy Welling fell while rappelling the large waterfall because the rope released from the figure 8 block rigged by her partner. About 10 ft of tail remained behind the figure 8 block, and it apparently pulled through the figure 8 block dropping Joy. The failure was not observed by Joy's partner, so it is not known exactly how the block failed. The figure 8 block was reported not to have had a "twist" nor a safety carabiner through the small eye of the figure 8.
Because there was no safety carabiner to prevent the second loop of the figure 8 block from coming off, movement of the rope during rappel may have caused the second loop to fall off leaving just one pass through the figure 8 as friction. This would have led the rope to pass through the block fairly quickly after the second loop came off.
Some figure 8 block variations can release (allow the rope to slide through them) if the figure 8 is pulled away from the quick link. This is because the quick link works with the figure 8 to pinch the rope in the desired way, and that pinch sometimes fails to happen if the figure 8 block is not up against a quick link. See the video below for a more detailed explanation. If the rope shifted while Joy was on rappel, the edges of the figure 8 may have been caught on a rock feature causing the rope to release.
The primary lesson of this accident appears to be that unprotected short tails on contingency anchors should be avoided. This lesson did not appear to be common knowledge among canyoneers at the time of the incident (see SoCal Canyoneering discussion). There are a few specific possible preventative measures in addition:
Always use safety carabiner
If the cause of the accident was that the second loop came off the figure 8 block, then attaching a safety carabiner to the small eye of the figure 8 and to the pull rope would have likely prevented that loop from coming off.
NOTE: A safety biner would NOT prevent the failure in the above video, where the ropes slides through the 8 (at 3:30) rather than popping off the loop. These are two different types of failures on the figure 8 block.
Use a capturing twist
In some variations of the Figure 8 block, a high-tension strand passes over a low-tension strand preventing the rope from slipping even if the carabiner is separated from the quick link. If the cause of the accident was the figure 8 and quick link separating (as in the above video at 3:30), using a capturing twist would likely have prevented the accident. The capturing twist can make the block more difficult to release however, and therefore should not be used in all situations (specifically situations where timely release is essential, like a strong waterfall).
When the tail of a contingency block is short (as it was in this case), putting a stopper knot in its end should prevent the rope from pulling all the way through as it did in this accident.
Tie ropes together before rappelling
If using a short-tailed contingency block, an alternative to tying a stopper knot is simply to tie the retrieval rope to the short tail before rappelling.