We are so spoiled here in the land of endless sunshine, that we forget about the rest of the US and the rainfall they experience. We get so little rain here annually that a roof could have a leak, and we would not know it for months, or even years. Concrete tile roofs are not waterproof. They are heat resistant, designed to provide an air barrier against the hot summer sun here in the Mojave Desert. Rain can, and does enter the attic spaces, usually in small amounts, but on occasion, as with a damaged roof, in larger amounts. In fact, roof leaks dry up most of the time in the arid desert air inside the attic before we ever see the evidence of them inside the home, such as a moisture stain on a ceiling.
Having a few days of constant rain provides repair work for roofers, as people finally realize that there is an opening, or leak in their roof envelope, which should be repaired. As a structural inspector (homes), we can see roof leaks much easier with the constant rain. We also take our infrared cameras into the attic spaces to scan for moisture intrusion. Scanning the home's ceilings, walls, and floors allows us to visualize leaks before they can be seen with the naked eye.
So next time you worry about a few days of rain, realize that the rain clouds have a silver lining as a roof leak will appear if there are hidden openings in the roof materials, and once the rain stops, as it always does here in the desert, you will be able to have it professionally repaired.
Was it Elvis that sang "Rain, Rain, Go Away, Come Again Some Other Day...?"