Stonefall—happened one evening, June 2007; no-one below luckily. This section was due for demolition—just hadn’t got round to it. Guess I got away with this one with just a bit of scrappy boarding getting smashed and buried by the rubble.
In the image below, I’ve zeroed in on the unstable area prior to the collapse. We were in the process of removing the original large and heavy flat stones along the top of the wall. Once a roof has gone on a crude stone building like this, the weather and rain get in, and then when the frost comes, water freezes, expands, and gradually “blows” the wall. This collapse, however, well illustrates the structure of the dry stone wall (the Double) — the outside face stone collapsed, leaving the inner face still in place.