Ice dams in Seattle form when warm attics melt snow that refreezes at eaves, forcing water under shingles

https://trentonqcie977.tearosediner.net/how-to-handle-seattle-roof-insurance-claims-fast-1

Ice dams in Seattle form when warm attics melt snow that refreezes at eaves, forcing water under shingles. Continuous soffit-to-ridge ventilation, air sealing, and eave ice-and-water shield stop hidden winter leaks.