What's that White Stuff?

It's not every day that you see something that resembles snow in Southern California. The day after I arrived back from the warm tropics of South America, I was greeted by this in my yard. It was slightly hailish, but sure was white. Maybe it was "snail". This is doing its best to chase even the extreme Californians out of their flip-flops. And rumor has it that we've been advised to put chains on our tires should we get a mighty snowfall of an entire two inches. (Don't scoff, all you mid-westerners.)