Heather Slavey squinted as she stared into the badlands. She shook her head in awe of the natural montage — yellows, pinks, purples. “Wow,” she said. “It looks like something out of the Wizard of Oz.” Slavey, who does marketing for a law firm, and her husband, Robert, left their home in San Diego early Saturday morning, and drove toward Anza-Borrego Desert State Park. Like thousands of others across the Southland, they made the pilgrimage into the desert this weekend to witness a once-in-a-decade wildflower “super bloom” — the aftereffect of heavy winter rains.