Just before dawn, erratic wind gusts whirl sand and dust into the crisp October air in Coachella Valley as a pair of tinted-window tour buses pull into a cul-de-sac at the United States Border Patrol station in Indio, Calif. The buses park strategically obscuring the entrance to a compound whose pale-yellow walls are crowned with barbed-wire rails. Moments later a crowd of migrants gathers in the narrow space between the gate of the compound and the buses where an official holding a clipboard waits at a portable table. As the sun begins to draw the mountains out of the distant darkness, the unsettling winds subside. Cristian, his wife, Estella, and their two-year-old daughter, Cristina, board one of the buses. It’s the best day so far in their perilous 10-day journey from war-torn Colombia. Their bus soon arrives at a hotel where Gloria Gomez, cofounder of the Galilee Center, welcomes about …