The first thing Brown does is examine the trail map to find the runs that face north. "That's where the snow is the most dependable," he says. "It's the least affected by the sun, so it remains the driest. One of the reasons (Colorado's) Arapahoe Basin can offer great skiing in May and June is that it has great north-facing slopes. The snow stays colder, and it never gets direct sunlight. There's no melt-out at all." If you can't judge by the sun, use a compass or look for shadows on trail maps that reveal which way is north. Most mountains post online versions of their maps, which Brown often uses to select his first run-before he even arrives in town.