Does anyone know why there are two mixed division tier III's sections? Why wouldn't they have all of the mixed division tier III choirs compete against each other?
California's divisions are by self-reported skill level. Advanced, intermediate, and novice. Tiers I & II are advanced tier I and advanced tier II. Those tier I groups are... slightly more advanced??? The double Tier III's on here are intermediate and don't seem to be discernibly split in any particular way. I'm not sure about here at Burbank, but I think Häakon posted that for Los Al's comp intermediate is split into two sessions for spatial reasons of only having a certain number of choirs per session. And then the Tier IV division listed here is novice. Make sense?
Actually nowadays in California, tiers 1 and 2 are actually advanced large and advanced small. I believe the cutoff for small is 40 members but I’m not sure. Tier 3 is also split into small and large.
I think it’s more a size of the auditorium thing - to be able to have all of the competing choirs (and an audience) in the auditorium at the same time.
Jacob's question is totally valid, and I agree, it's confusing and strange. If they are indeed now splitting all Tiers by choir size (or, arbitrarily, just 1-3?), then Tier III "small" should just be Tier IV (just like they've split Tiers I & II by size). If it's for auditorium capacity reasons, then whatever... but then no distinction should be made about group sizes. I'm not sure that information is accurate. Either way, the number of splits is getting pretty out of hand... California used to have the most elegant solution (three simple-to-understand, skill-level tiers), and now it's fractured into a mess of skill and choir sizes and more levels than anyone can keep track. When a midwest prep group visits, where do they belong? Tier II? Tier III? Tier IVB? It's no wonder people are having difficulty understanding the presentation.
I agree that it’s all very confusing. After being at Blast all day yesterday, it seemed like the Intermediate Mixed Tier III split into 2 groups was basically arbitrary, because they had 10 groups and couldn’t fit them all into one auditorium along with audience members. But for the Advanced Mixed and Advanced Treble, the Tier I/II split was based on size. The Tier I groups all had 40+ performers, whereas the Tier II groups were all half that size.
I guess is also good cuz groups like Burbank, Burroughs and Los Al dominate so now the intermediate groups and advanced women’s groups are given chances depending on if their large or small
The double Tier III's on here are intermediate and don't seem to be discernibly split in any particular way. I'm not sure about here at Burbank, but I think Häakon posted that for Los Al's comp intermediate is split into two sessions for spatial reasons of only having a certain number of choirs per session. And then the Tier IV division listed here is novice. Make sense? 
Brooke Bailey - John Burroughs “Powerhouse”
Ethan de la Motta - Brea Olinda “Masquerade”
Unfortunately I do not remember the third one.