The G Trail, part of the Winter Grooming Snowmobile system for over-snow vehicle (OSV)/snowmobile use, represents the majority of the main winter trail between Mammoth Lakes and June Lake Junction. Groomed and marked with orange diamonds, the trail begins from the OSV tunnel under Hwy 395 and stays on the west side of the highway. After crossing the Mammoth Scenic Loop, it heads out across the open, scenic terrain of Dry Creek Flats, then climbs to Obsidian Dome, once an important source of volcanic glass for native arrowheads. There is a general store and gas station at the junction of Highway 395 and Highway 158. The Winter Grooming Snowmobile System is groomed by the U.S. Forest Service with funding provided by the California Department of Parks and Recreation, using monies generated by registration fees and gasoline taxes.