Regarding Ice - Much of the damage from Ice accumulation on a building is commonly missed. On a residence, "ice damage" and the ensuing melt that can cause considerable water invasion to a home is commonly dismissed as a water stain on a ceiling that needs to be repainted.
However, the melting of ice from the underside (the surface that is in contact with the home) causes water to basically submerge the shingles. Shingles are designed to shed water that is running down a slope. They are not, however, designed to resist the equivalent to standing water. Significant amounts of water can drip into an attic, saturating the insulation, decking, rafters, and plywood decking supporting the roof and the plywood used for the attic flooring.
Given that the melting process is slow, considerable fungal growth can setup in the attic during this process, given the steady supply of water for days. This could result in the establishment of a fungal colony that can grow to a serious issue as the weather becomes more conducive to active fungal growth. When you have a stain from an ice storm, it would be prudent to have a 3rd party examine the area of the attic above the stain before a potential problem becomes a serious problem.
Ice can also create similar problems with commercial roofs. Here in the south, many flat roof systems in existence were not designed by the same standards as used today. In many cases, these structures will deflect with the weight of snow and ice that has impacted this area of the country over the last few years.
This deflection, although not readily noticeable to the eye, can be significant enough to stretch seams of a membrane roof and or the joints at roof penetrations to a point where they begin to leak. Because these leaks don't always make it to a ceiling tile below, an owner that has spotted one stain, may, in reality, have dozens of leaks. In fact, these joint and seam failures may not manifest themselves into a full blown leak until a wind event or a significant rain event follows and pushes the problem area over the edge, whereby the joint or seam actually fails sufficiently to let a major amount of water in.
If you suspect that evidence of water invasion during the ensuing months after an ice and /or snow storm may be related the the ice or snow storm, you may want to have a 3rd party consultant examine the roof to determine the cause and origin of the leak prior to it becoming a significant water event.