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

https://marcoiqig511.cavandoragh.org/seattle-s-2026-building-codes-what-homeowners-must-know-before-a-roof-replacement

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.