- Leaking roof (height of leak depends on extent of ice dam).
- Wet, ineffective insulation.
- Stained or cracked plaster or drywall.
- Rotting timber.
- Stained, blistered or peeling paint.
Under extreme conditions, with heavy snow and severe cold, almost any house can have an ice dam, whereas a house that is poorly insulated with attic bypasses will have ice dams during a normal winter weather. Giant icicles hanging from the eave are one indication of a poorly insulated attic with many attic bypasses.
Although high snow levels along with extreme cold weather is generally considered the highest potential risk conditions for ice dams to accumulate, standing snow is not even a required prerequisite for ice dams to form. It takes very little actual moisture to form ice dams.