The answer to 'roof ice dam' is that a roof ice dam is a buildup of ice at the edge of a roof that can prevent proper drainage and lead to water damage. Common causes include poor insulation, inadequate ventilation, and heavy snowfall. Symptoms include icicles forming along the roof edge, water backing up under shingles, and interior water damage.
The best solutions are to prevent ice dams from forming in the first place. This involves improving insulation and ventilation in the attic, removing snow from the roof, and using heat cables or other de-icing methods. If an ice dam has already formed, you can try to melt it using calcium chloride ice melt or by carefully removing snow and ice. However, if the problem is severe or recurring, it's best to call a professional roofer to inspect the roof and provide a long-term solution.