I didn’t know that ever happened. The roof of our apartment building began to leak immediately, and we’re on the top floor, so now the kitchen is full of water. I suppose this happens so rarely that it isn’t worth worrying about. There are no storm drains alongside roads, so they may hold water, and I doubt if the local drivers have a lot of experience with driving in water, so maybe accidents increase. When I moved to San Francisco in January of 1976 it snowed. The whole city shut down. Nobody knew what to do with snow. It melted by the afternoon and never happened again during the twelve years I lived there.