The Perfect Storm

The perfect storm – keep an eye on your rigging

We were on a canyoning trip recently when we were using a figure-8 abseil device as a block. Over the last eight years, I have probably rigged it over 500 times and never had an issue. However, on this occasion, all the holes in the Swiss cheese nearly aligned until we got down to the final defence – the safety check.

Hold on don’t abseil yet, that doesn’t look right.

At the time I thought, how could that happen, it would seem pretty unlikely. Later I tried to replicate the failure and found that it wasn’t too hard at all.

For those not familiar with canyoning, the figure-8 device is a releasable block. If an abseiler gets stuck, you have a way of immediate rescue by either lowering or converting to a raise. The main advantage of this style of block is efficiency as the rope is already set up for retrieval. All the last canyoner needs to do is change the quickdraw attachment from the anchor to the retrieval rope.

Blocked Figure-8 Device
Figure-8 Device Block

The situation

  • Abseiling from a two-bolt chain linked inline anchor station
  • A rope threaded through the anchor ring
  • A figure-8 device block backed up with a quickdraw
  • The quickdraw clipped to part of the anchor chain
  • The back hanger had a pack attached to it
  • A safety handline attached into the anchor ring
  • Anchors were located around 5m horizontally back from the edge
  • The abseil was down a 25m waterfall

What happened

  • A loop formed on the retrieval rope (untensioned).

    Loop formed on the untensioned rope
    • This loop fed over the top of the figure-8 device and pulled the quick draw sling through the large hole. When we did a final safety check, this is how we found it.

Quickdraw pulled through the large hole

Testing

When we tested the setup, it allowed the rope to run through the figure-8 device at less than body weight.

  • Rock Exotica Enforcer Load Cell
  • 5:1 pulley system
  • Range 0.26kN to 0.70kN
  • Check out the video at the end

Underlying causes and contributing factors

Absent or failed defences

  • The final safety check picked up the issue before it became an incident

Team or individual actions

  • Weight was going on and off the anchor as the abseiler was moving horizontally to the edge
  • Movement from a hand line rigged from the same anchor ring
  • The other rigging point (top bolt hanger) was used to hang a pack

Task and environmental conditions

  • Had descended the canyon many times – 5 times that season and approx 15-20 times before that – very familiar with the location
  • Cold canyoning day at the end of the season, had lots of warm gear on, hats made comms more difficult
  • Started abseiling away from the anchor so harder to check/weight the system
  • The rope was stiff

Organisational

  • The accepted practice for canyoning
  • Had used it for years without problems

Learnings (and things we will keep doing)

Rigging

  1. Clipping the retrieval rope through the carabiner on the small hole of the 8 would help prevent it – would not allow the loop to form in the same way.

Clip the retrieval rope into the carabiner

2. Keep the quickdraw tight where you can. However, this is not always possible.

Keep the quickdraw tight

3. Keep the ring/master point clear of any other rigging (as much as possible).

4. Use a rigging carabiner for additional attachments, e.g., packs, cowstails and handlines.

5. Safety Check – anchor rigging, self, and buddy!!! Do it every time you get on the rope. Your life depends on it.

Download the attached guide height safety ABCs:

Height Safety ABCs

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  1. Recognise pitches/starts that present more challenging situations to safety check before loading your system – e.g., remote anchors, horizontal movement. Communicate and work as a team.
  2. Awareness when using a stiff rope. Will your rigging set and stay in the same place?

Group management – decision making and human skills

  1. With the group talk about the day’s canyoning and any factors that might change or influence how you operate on that day, e.g. cold weather, roles, less or more experience, comms methods, injuries etc
  2. If you are unsure, or something doesn’t look right, or you feel uncomfortable about something there is a reason. Work on a culture where anyone can speak up about anything at any time. Questioning is good.

Final thoughts

  1. As a team, we debriefed the event and realised we all played a part.
  2. There is both technical and group management learning. It’s rarely a technical failure on its own.
  3. Always keep learning, trying to improve your practice and sharing your experiences with others.
  4. Understand how incidents occur gives you insight. Put things in place to prevent you from getting to the last line of defence.
  5. We manage risk in a dynamic environment in the outdoors. Sometimes when the unexpected occurs, and the situation or conditions change, and we have not ‘experienced’ it before all we have left is our defences.

If the perfect storm arrives are you ready?

Grant at Over The Edge Rescue.