Nothing like the first day of skiing to test one’s mental and physical mettle. With the opening of Spar Gulch, Aspenites again have their baby back.Laps on Aspen Mountain can result in the zenlike state that always settles in during physical exertion. But that usually comes in only after the new-season pain has worn off. The feet, calves and thighs have to get used to the grind they are about to go through.Sometimes, there are mitigating factors for the pain, and last weekend’s 20-inch dumping helped enormously. There is a 20-to-25-inch base on Ajax, which is 60 percent open. The top of the hill was fantastic this week, offering soft groomers such as Silver Bell and untapped powder on Bell Mountain.At the bottom, where man-made snow reigns, things were obviously a bit icier. Negotiating the narrow and bumpy egress at the bottom of Little Nell provided a final bit of excitement.At Snowmass, the base is 26-36 inches and 558 acres are open, with more terrain opening today.Speaking of opening today, Sunlight does. A hearty welcome back to our downvalley cousin.Back up here, bootpacking has begun at Aspen Highlands. Truly dedicated skiers and boarders have been laboring away in the Steeplechase area. Bootpackers also saw remnants of a natural avalanche that let loose on The Wall, a run on the upper part of Highlands (not to be confused with the Hanging Valley Wall at Snowmass).Now included in The Associated Press daily ski report are descriptions of conditions at the Ashcroft and Aspen cross-country centers. The former has a 12-inch base and one of 20 trails open, while the latter has a 5-inch base on 11 of 14 trails.Think snow.