Fort Tuthill County Park is open and free for passive slow play recreation. There is no dedicated sledding hill however.
Flagstaff Snow Park, which is located in Fort Tuthill County Park, makes snow in a dedicated area with tubing runs. Their website has more information and a link to purchase tickets, which are required to recreate in this area of the park.
For other sledding and snow play areas in and around Flagstaff, the City of Flagstaff publishes a winter recreation map and operates a winter snow play information line at 1-844-256-SNOW.