Ice dams form when heat loss through the roof melts snow on the roof. The meltwater flows to the cold eave overhang where it refreezes. This ongoing process causes ice to build up and create a dam, eventually preventing upslope meltwater from draining off the roof. If proper ice dam protection is not provided, ponded water can back up under the roofing system and cause building leaks.
Ice dams not only concentrate snow and ice loads at the eave, but can also contribute to water leakage into buildings. Unaddressed water leakage can cause structural deterioration and may not stop until the snow and ice is removed from the roof.
You can try to do the follwing tips:
1. Remove snow from the roof. This eliminates one of the ingredients necessary for ice dam formation.
2. ventilate roof eaves and ridge
3. insulate and seal the attic hatch access
4. exhaust to the outside
5. add additional attic insulation
6. install sealed-can Ceiling lights
7. flash around chimneys
8. seal and insulate ducts
9. caulk all ceiling penetrations