Snowmobile trails in Oneida and Vilas counties are closed as of Thursday afternoon.
John Bilogan, Director of the Oneida County Forestry Department says warm weather has melted most of the snow.
"If you get into the woods, the trails probably would still be ridable. But it gets to the point where intersections and areas that are exposed to direct sunlight, a lot of them are bare."
Bilogan says riding on bare ground can cause safety issues or damage to trails.
"And of course we look at safety hazards, and possible doing damage to private landowners' property, rutting and things like that."
Last year many trails stayed open through the end of March.
Forest, Iron, Price, Lincoln, Langlade, Ashland and Bayfield counties have also closed snowmobile trails for the season.
Trails in Upper Michigan remain open but groomers say conditions are poor.
Meanwhile the Chequamegon-Nicolet National Forest has also closed its trails to all snowmobile, ATV, bicycle and horse traffic until the end of the spring thaw, to avoid damage to trails.