When does Dolly Sods open and close for the season?

Dolly Sods is always open as part of the National Forest Service, though access to the park roads could be restricted if there's a lot of snow--but it's a killer place to cross-country ski or snowshoe during the winter. Autumn and spring are also wonderful, and it's a nice place to visit in the summer because the higher elevation affords cooler temps then elsewhere in the Monongahela NF.