Following the wiki trail, it looks like Critical Heat Flux (CHF) is part of the phenomenon I'm interested in. http://en.wikipedia.org/wiki/Critical_heat_flux
Interesting stuff. This may explain why my brew pot sometimes gets a caramel stain on the bottom in the shape of my burner. This is apparently happening in the absense of direct contact with the water. Instinct told me that a kettle wouldn't scorch that was in contact with water, so it was a bit of a mystery. Turns out, the reason it scorches, is that the water is seperated by a film of steam when input temps reaches a certain (condition variable) point.
It may also explain how sometimes just as a boil starts to roll, it can fall back down and cycle despite the heat source remaining constant. Once that film develops, heat transfer is reduced. I can certainly see why having a wide pattern burner is advantageous.