In reply to UKC Articles:
I once had a bizarre experience when practising self arrest on the lower slopes of Mam Tor.
Me and my mate tried various starting positions, throwing ourselves down the slope face up feet first, face down head first, on our backs feet first etc. etc..
On the final attempt which was something like on my back head first, I successfully rolled over and let my feet swing down and proceed to slow down but suddenly I must have hit a bump, and I stabbed myself in the throat with some part of the axe, not sure which. The pain was excruciating, and was accompanied by a really strong smell of sulphur, which in my panic I thought was something to do with puncturing my windpipe, or dying or something.
I gingerly stood up, and my mate confirmed no visible damage to the throat. But where was the strong sulphur smell coming from?
I felt in my duvet's inside chest pocket and retrieved a box of matches, which I opened to discover that every match had ignited and burnt. The friction when sliding on my chest had created sufficient heat to ignite them, even through a layer of down.