Roofing materials are rated for their resistance to penetration from hail. A UL 2218 test Class 4 is most resistant (rating range from Class 1 to 4). The rating does not, however, mean that a roofing material will not have cosmetic damage like dents. FM 4473 is a newer hail impact testing standard for clay, concrete and slate roofing, that rates materials from Class 1 to Class 4 (most resistant)..
To guard against burst pipes in unusually cold weather, locate all plumbing inside the insulated building envelope. Avoid placing plumbing in vented attics and exterior walls. The flexibility of PEX piping makes it resistant to breaking from freezing water in the lines. Still, all piping in unheated space should be insulated.