Falling ice perplexes scientists / Theories abound after 2 chunks land in state in a week

"The skies are raining big chunks of ice, and experts ranging from scientists to federal investigators are scrambling to learn what's going on.

For the second time in a week, California was the victim of an aerial, icy assault, the latest being early Thursday when a chunk of ice the size of a microwave oven plunged out of a cloudless sky into the San Bernardino County town of Loma Linda. The ice punched through the metal roof of a recreation center, leaving a hole up to 2 1/2 feet wide, then fragmented into opaque, brilliant white chunks, one as big as a bowling ball. No one was hurt."

Click the title to read about possible explanations