Had an interesting failure of the mast on my ice boat many years ago. Excessive bending midway between the deck and the hounds. Initial failure was apparently in compression on the inside of the bend. The mast showed definate lines of compressed wood, these lines being about a foot apart. I think they're called 'Luders lines'. As the wood failed in compression, the section modulus got smaller and finally the outer fibers in tension reached their limit - and these came apart looking like two narrow pieces of brooms. Many long splinters of sitka spruce.
Thinking back on it, the compression failure may have started at a dent on the side of the mast. This dent was caused by a side stay failing previously, allowing the mast to fall onto the leeward runner.
Sailing ice boats is a blast. If you get the opportunity, give it a try (dress warmly). They go the fastest right before they come apart!