Snowbird's FB page has been displaying a lot of pow pictures recently.
Latest I've ever ridden there was early April but had some prime conditions. I know they are often open through Memorial Day and sometimes beyond. They are at 407" YTD right now which I think is about 80% of what they get in an average season, so overall snow totals are lagging a bit. But if they have had a few late-season storms to pad the base, that shouldn't matter much. They have 10 feet of base right now, that's not going to melt away any time soon.
I would still expect warm & slushy to be the flavor of the day, that late in the season though.
Is it worth it? I'd do it if I were you