Most ski resorts open when there is at least 3 or 4 feet of snow, depending on the terrain. The exception would be those that have an all-year program of things to do there.In my area (in and around...
All that have a glacier which at least in Europe are quite many. Also resort that are located far north like Björkliden and Riksgränsen in Sweden. Chamonix in France is open in May, also open:...