Removing accumulated snow and ice from the roof can help prevent future interior water damage. Roof dam warning signs may be visible from building exteriors:
- Icicles at the roof edge
- Ice accumulation in the rain gutter and edge of the roof
- Ice in soffit vents
- Ice on exterior siding
- Ice or excessive moisture accumulation on interior window cases and sills
Along with water damage to building interiors, accumulated snow on the roof can cause roof failure or collapse. FEMA publishes snow load safety information here, the National Weather Service in Juneau AK published snow load calculations here and Purdue University offers a comprehensive calculation formula here.