The answer to 'why is my downspouts ice dams' is that ice dams are caused by a buildup of ice at the edge of your roof, often near the downspouts. This can happen when warm air from your home escapes into the attic and melts snow on the roof, only for that water to refreeze at the colder roof edges. This blocks the downspouts and prevents proper drainage, leading to ice dams.
Some common symptoms of ice dams include icicles forming on the gutters, water leaking into your home, and damage to the roof and siding. Solutions can include improving attic insulation, sealing air leaks, and clearing snow and ice from the roof. However, dealing with ice dams can be dangerous, so it's often best to call a professional roofer to assess the situation and provide the proper remedies.