Xazier Bias walked out of the Whole Food Market in Pasadena and saw another woman looking to the ground puzzled at the white stuff covering the sidewalk. The woman wasn’t sure exactly what she was looking at. But Bias, who is originally from the East Coast, quickly set her straight. It was snow. “People didn’t know what it was,” Bias said. “I was like, no, this is snow.” It was that kind of day in some parts of Southern California, which saw snow level plunge to extremely low levels, creating a winter wonderland, at least for a minutes. Snow fell...