The answer to 'why is my flashing ice dams' is that ice dams are a common problem that can cause water damage to your roof and home. Ice dams form when heat escapes from your home, melting snow on the roof. The melted snow then refreezes at the roof's edge, creating a dam that prevents further drainage. This can cause water to back up under the shingles and leak into your home through the flashing around chimneys, vents, and other roof penetrations.
Some common causes of ice dams include poor attic insulation, inadequate ventilation, and clogged gutters. Symptoms can include icicles forming at the roof's edge, water stains on ceilings and walls, and damage to shingles and flashing. Solutions may involve improving insulation, adding roof vents, clearing gutters, and in some cases, installing heat cables or de-icing systems. In severe cases, it's best to call a professional roofing contractor to assess the problem and provide the proper solution.