In the Redmond area, roof repairs are often due to damage inflicted by ice dams. Ice dams are thick, heavy ridges of ice that can be found at the edge of the roof. If not addressed promptly, ice dams can cause significant damage to your home, and require costly roof repairs. It is possible to prevent ice dams, even in northern climates. A roofing company can help you with this. 
Why Ice Dams Form
Ice dams develop when certain wintry conditions are met. First, the roof must have snow on top of it. Second, the higher elevations of the roof must be above freezing on the exterior, and the lower part of the roof must be below 32 degrees Fahrenheit. These temperatures, if sustained over time, will cause the snow at the higher elevation to melt. The water will run down the roof, and freeze at the lower section. The result is an ice dam.
How Ice Dams Cause Water Damage
Once an ice dam forms at the edge, snow continues to melt and flow down toward the dam. The freezing water will make the ice dam grow larger. Once the dam is large enough, the melting snow will no longer reach the parts of the roof that are at or below the freezing point. It will remain liquid, and this allows it to seep into cracks. The result is water damage in the attic, and eventually, the lower parts of the home.
How to Prevent Ice Dams
It’s possible for homes to be more susceptible to ice dams if the roofs weren’t properly installed. Consider asking a reputable roofing company to do an inspection. To prevent future damage throughout your home, it may be worthwhile to get a roof replacement before the next winter. Other steps to take include sealing all areas in the ceiling to prevent heated air from transferring from the main part of the house up to the attic. Heated air in the attic will cause the top of the roof to warm up, which allows snow to melt and form ice dams. Some homeowners take the extra step of having additional insulation placed in the attic.