Do ice dams damage the shingles? How common is this?
Dennis Rich, P.E.: Ice dams can cause damage to shingles by causing water to back up under the shingle, freeze, and lift the shingle, thereby causing the shingle to tear and delaminate the underlying shingle along the seal strip. During cold weather, shingles are more brittle and susceptible to cracking or splitting when lifted. Also, once the seal is broken, there is no guarantee that shingle will properly reseal. Damage due to ice dams is not commonplace, but it does occur.