Red Flags - warnings that an anchor is poorly chosen, poorly rigged, or poor in general. We often ignore Red Flags, but if you wanna LIVE!, you should not. (Red Flags show up in many accident reports, often as 'we noticed this was off, but we did not have the time to fix it'). "Approaching the Grim Crawl, we came across a chockstone that had been slung as a rappel anchor. It was a long way back from the edge, and it looked like a previous party had used all their webbing to try to extend it. The chock was slung with a length of bright red webbing, which led to a length of bright yellow webbing that ended 15 feet short of the lip. One member of our group remembers seeing the webbing tied together with a single flat overhand (like an EDK, not a water knot) and thinking that the tail was much too short. Another party member said that the slung chockstone was in poor form and wanted to chop it, but he wasn't carrying a knife. We discussed the best way forward and decided that rappelling off of the slung chockstone would be fastest if un-stylish (and we were burning daylight! [and planned to do two canyons that day])." Result: The first person rappelled to the ground. When the second person moved over the edge, the knot joining the two pieces of webbing parted. The second person fell about 30 feet to the bottom, and got banged up but not seriously hurt. The group retreated upcanyon and exited at the established escape route without further incident. Red Flags - about the anchor: 1. Choosing an anchor far back from the edge - poor form, rookie move. 1b. Anchor does not match beta description in well-established canyon. In this case, having a 'fixed anchor' in this location is contrary to the beta; this indicates the party that put in that anchor was of low competence. 2. Use of bright webbing - poor form, rookie move. 3. Webbing joined with non-standard knot - definitely an indication of someone who does not know what they are doing. Red Flags2 - Red Flags in relation to the leadership or lack thereof of this group: 1. "but he wasn't carrying a knife." - the group lacked essential standard gear. Whereas not every person in the group needs to carry a knife, someone does. 2. "as a solidly intermediate group of four" - Overly optimistic evaluation of skill level... near the peak of Dunning-Kruger. 3. "This was his first time ascending, so he got to endure some on-the-spot training with the usual floundering. It probably would have been a good thing to practice..." - see #2 above. Tom's #1 Rule for staying alive: Don't be a beginner being led by a beginner. (Corollary: Don't be a beginner leading beginners). Note: this Rule applies even when the beginner claims to be a "solid intermediate". Note on Progressive Failure: This is a good example of progressive failure. PF is when something fails from repeated loading, a bit of failure each time, then true failure all at once. We mostly think of failures as 'wasn't strong enough'. PF is when it is strong enough at first, but eventually it is not strong enough. Knot chocks are especially prone to this kind of failure, but many anchors and anchor riggings can demonstrate this kind of failure. Thank you to @Michael W for providing an excellent report on this accident.