Hyalite road is closed from approximately April 15 to May 15.
This is a quick loop and as such is very popular. It is not uncommon to see multiple cars at the trailhead before dawn. As such the skin track is pretty much always in but the three distinct powder fields that make up most common descent route can actually turn into mogul fields from over use.
Park at the History Rock trailhead and follow the trail popular with backcountry skiiers, nordic skiiers, and snowshoe'ers. Head from the parking lot across the meadow, then into the woods, making a sharp left. Follow the singletrack uphill past "History Rock", then through a few open meadows. The trail makes a slight right-hand turn and the real ascent begins. Follow the switchbacks uphill, then as it eases out you'll follow the trail in a left sweeping direction following a gentle nose feature of the landscape. One last mellow climb reaches the "summit" of the zone where you can lap the main powder field 'til your hearts content.