#1 Interior Water Damage
Ice dams can allow water to seep into your home. If you notice evidence of water damage you should check your roof.
#2 Ice on Exterior Walls
If you notice ice forming on exterior walls, beneath siding, behind the soffit, or in any other odd places an ice dam may be the culprit. As water backs up on the roof eave, it can seep in and behind surfaces and refreeze. During warmer weather, this may be visible as water stains.
#3 Gutters Not Draining
If your gutters aren’t draining, you may have ice dams causing the water to back up on your roof. If left unchecked this water can work its way into the structure, or freeze and damage the roofing material.
#4 Icicles Form at Roof/Gutter Edge
Icicles can be an indicator of an ice dam. Icicles along your gutter edge indicate that water is not draining properly. If these icicles are causing backup on the roof, you can wind up with damage.
#5 Snow Melts High on the Roof, But Not Low
Ice dams form when melted snow and ice refreeze on the roof eave. If you have snow and ice buildup low on your roof, but things are clear higher up, then this can indicate an ice dam.