Can you provide some guidance for fighting ice dams?

Here is some information to help fight ice dams.

Ice dams are a combination of two factors: weather and heat loss from the living space. Sometimes the weather can be just right for ice dam conditions and despite all precautions to prevent an ice dam, ice dams may still occur. The best defenses may be in place, but if the snow melts during the day and refreezes and snows again at night, the cycle will persist and cause significant ice dams. Heat loss is the cause of the snow melting from a warm attic heating the underside of the roof deck. The best way to combat this is attic insulation. Another way that heat can be lost to the attic is through air passages from the heated living space into the attic. These attic bypasses include unsealed/un-insulated attic access hatch, recessed can lights, plumbing or duct penetrations, open wall cavities, bathroom exhaust fans, leaky heating ducts, etc. All of these can lead to enough heat escaping into the attic to cause an ice dam. The best way to prevent ice dams is to incorporate attic insulation, attic ventilation, and waterproofing shingle underlayment. Attic insulation minimizes heat loss from the living space into the attic. Attic ventilation helps create a uniform roof deck temperature and minimize extreme hot and cold spots. Waterproofing shingle underlayment minimizes the damage should an ice dam occur. Other strategies for fighting ice dams may not work as well. The use of heating strips is not recommended because they can be dangerous, costly, can use quite a bit of energy, and really will not work well. While a heating strip may prevent an ice dam near the gutters it may move the starting point further up the roofline.  Salt may work; unfortunately, it can ruin plants and shrubbery around the home.  Steaming the ice off the roof is another strategy, however, it can be quite expensive. Roof rakes could be used to pull down the snow and ice from the roof, but one must be careful in these cases that ice and snow falling from the roof does not injure someone. Be careful not to damage the asphalt shingles, too. Power vents are not ideal for ice dam prevention. Although power vents are equipped with a humidistat so that they will run in the wintertime, it does not mean they will come on to prevent ice dams. Ice dams form from heat loss not from humidity, so typically installing a power vent equipped with a humidistat with the intent to prevent ice dams is not the way to go. A power fan would need to be equipped with a logic controller which would sense when ice dam conditions were right and turn the fan on to exhaust heat from the attic.