I don't normally stock the dry yeast but there is a health food store here in town that carries a small supply of homebrewing stuff. They have helped me out in a pinch before though they are hit or miss. Since I'm using California Ale I'm thinking that is common enough that the health food store might have something I can use. I think they might have some dry yeast as well so if I have to I can go get some from them.
I did let the stuff thaw and made a starter with it. It seems to be doing its thing just fine, lots of activity actually, I have no doubt about the living cells in the flask. My concern is that the low temps, though not killing the yeast, may have done something to their cell walls or something?
I'm also wondering if maybe the yeast didn't freeze but the nutrient inside the tube did? Is that possible?
Right now, given the apparent health of the starter I'm leaning toward using the yeast.
Emergency yeast is a good idea that I haven't thought of. I'm thinking I should get some now regardless of this incident