Although its true that the snow is melting fast there are still several good options out there, so don't worry. I would put St. Mary's glacier pretty low on the options. It all depends how much you want to hike. Jones Pass is probably the best option for minimum hiking. Pretty much every step from the car can be skied on the way down, and it has way better snow and terrain the St. mary's glacier. Basically, St. Mary's glacier is flat and it even requires a short (20 min) hike before you even get to the snow. BTW St. Mary's is not a real glacier. Also consider Skyscraper Glacier (also not a real glacier) steep terrain with easy car access although you will of course have to hike back out. Trail ridge road also has lots of options close to the road. Sundown bowl is a sweet and kinda steep run off of trail ridge road with 5 min walk to the snow, but you will have to hike back up as far as you ski down. Feel free to PM me with any questions.