IDK what it is out west, and I'm gathering from the discussion here that it means something totally different to you western Divas. In the East, there is one, and exactly one meaning to "frozen granular": it's ice. Nothing but ice, and not going to turn into anything else during the day, just ice.
Frozen granular is how ski areas report any kind of ice. It's not a special kind of ice, and it's not limited to any particular phase of the snow cycle. It just means "ice". When you see it in a snow report, and ski areas in the East darned well better be reporting it, it's a gear and safety issue, you have to use a bunch of contextual clues to understand what it means. If it's rained and then the temperature has dropped, you're going to get "machine groomed frozen granular" which means death cookies for a day or two, and then it means 2" of pulverized ice chips on a surface of hardpack or boilerplate. If it hasn't rained, but it just hasn't snowed, then it means that you're getting the ice chips + hardpack (or as I think of it, New England Powder). Depending on atmospheric conditions, it might mean frozen cord, which is a really sucky surface. If it's snowed recently and you've got a couple of inches of fresh-ish snow sitting on top of hardpack, you'll get a snow report of packed powder/frozen granular.
Loose granular is not what happens when frozen gran gets groomed. Loose gran is what happens when frozen gran starts the melt-refreeze cycle, and it's basically like the stuff you get in a sno-cone. Loose gran does not usually go to mashed potatoes or the sticky snow - that's something that happens to a surface that was recently packed powder. What loose gran turns into if it changes during the day (which it usually does, since that's a spring condition here), it turns into slush, not anything else. Stuff strips the wax right off your skis, too.
