But four days later the sky darkens and it starts all over. By now, the soggy ground can't absorb another drop. The San Diego River overflows its banks and we see houses floating out into the bay. Dairy farmers flee their homesteads and lead their cows in swimming across the swollen river to higher ground. In the harbor, boats are swept from their moorings.
Bridges start collapsing.
In fact, before the storm is through, all but two of the city's 112 bridges will be washed away. The downpour overwhelms the city's filtration plant, so that even though San Diego is inundated with water, what comes out of the taps is unsafe to drink. In the mountains, dams start to strain and finally, on January 27, the wall of the Lower Otay Dam finally cracks under the stress, sending a 40-foot high cascade roaring down the slope. The wall of water rolls as far as the Tijuana racetrack, destroying everything in its path. Twenty people are drowned.