Symphony Bowl, Whistler.
7th Heaven, Blackcomb.
Already happened. Last season, January 18, Fernie BC, minus 27 Celsius, over 100 cm of light fresh snow overnight, and only a few willing to take on the cold. Every turn was effortless, so deep, you had to spit snow out on every turn, vision only when you came out of a turn, everyone had frostbite for the next 4 days. Most on the mountain agreed it was the best in 40 years.
Also, there's a little mom and pop ski area about 1.5 hours east of us, Castle Mountain in Alberta - antiquated lifts, but once you get to the top there's a 5 km. cat track where you can drop off all along for 2800 vertical on 40 degree slopes that last over a mile. When they get good dumps mid week, you and 2-300 others are skiing fresh tracks until 4PM - but go on the wrong day, and you might get blown off the mountain.
Kachina Peak - right to upper Hunziker Chute, down to the bowl, maybe right over to Totally Wireid ( sp?) into upper Staub, El Funko, then down to the Rio.
Or Upper Stauffenberg.
anywhere at Taos up high or down low... Werner chute to Longhorn --- or North American if you can find it.
Well my first choice would be JH - no crowds (is a fantasy) and tram laps down the Hobacks, but I haven't been able to be there for a 24 incher. I have been there for 10-12 multiple times and that was still fantastic, even with crowds.
A close second is Snowbird. In 2010, I was lucky enough to have hit Snowbird on two different days with 24 and 27 inches of fresh. Just did laps on the Tram, (hitting the Cirque and Baldy) till my legs finally gave out. By the way, even though it was a Saturday both times, the tram line wasn't that bad, AND the powder held all day cause it was still snowing - hard. I think the actual requirements: "24” Overnight. No Crowds. One run" is possible on occasion in Snowbird if you are up there overnight, AND the road is closed due to avalanche danger.
Europe - Top of Grand Motte cable car in Tignes down to Tignes Val Claret.... awesome long run and decent fun cruising gradient.
US - Off the Snowbird tram... either from Baldy or down off one of the pylons for the tram...
Snowbird! I would take the tram to the top and ski Cirque Traverse to Wilbere Bowl or Mach Schnell. Its not the most vertical feet or the craziest run, but its a run a really enjoy! Pretty much any double black diamond is going to be amazing with 24" and no other people!