About 15-hundred people were left without power yesterday after a funnel cloud ripped through South San Francisco. It struck about 3:40 p-m in the middle of a heavy thunderstorm, downing power lines, damaging rooftops and shattering windows. No injuries were immediately reported. It quickly moved east and dissipated over San Francisco Bay, but not before leaving behind rattled nerves. One resident said it “sounded like a freight train or a jet hitting” his house. Meteorologists from the National Weather Service will conduct a storm survey today to determine if the funnel was in fact a tornado — which is unusual for the Bay Area.