The answer to 'why is my asphalt shingles ice dams' is that ice dams are caused by a buildup of ice and snow on the roof, which can lead to leaks and damage to your asphalt shingles. This typically happens when heat escaping from your home melts snow on the upper parts of the roof, but the melted water refreezes at the roof's edge, creating a dam that prevents proper drainage.
Some common causes of ice dams on asphalt shingles include poor insulation in the attic, inadequate ventilation, and heat loss through the roof. Symptoms include icicles forming at the roof's edge, water leaking into the home, and potential damage to the shingles themselves. Solutions can include improving attic insulation, ensuring proper roof ventilation, and manually removing ice dams. However, some ice dam removal and prevention may require the expertise of a professional roofer, especially for larger or more complex roofs.