A tow-behind snow groomer for forming lanes with barrier mounds (in tubing parks or on ski slopes) includes first and second pans having bottom panels, with front panels and inner panels extending upwardly from the bottom panels, respectively. A central chamber between the first and second pans includes a chamber upper panel bridging the first and second pan inner panels. The groomer can be secured to a vehicle via a vehicle mounting plate. When the groomer is driven over snow, the groomer displaces snow such that the first and second pans form first and second lanes, respectively, with the central chamber forming a central mound between the first and second lanes. First and second wings facilitate formation of peripheral mounds. The central and peripheral mounds are at higher elevations than both the first and second lanes, helping tubers stay in one lane without crossing into other lanes.