The answer to 'why is my skylight ice dams' is that ice dams are caused by heat loss from your home escaping through the skylight and melting snow on the roof. This melted snow then refreezes at the edge of the roof, creating an ice dam that can prevent proper drainage and lead to leaks and water damage.
Common causes of skylight ice dams include poor insulation and ventilation around the skylight, air leaks, and inadequate roof slope. Symptoms include icicles forming around the skylight, water stains on the ceiling, and leaks. Solutions may include improving insulation, adding roof vents, and ensuring proper skylight installation and maintenance. In some cases, it's best to call a professional roofer to assess and address the issue.