Safely remove snow from the roof edge with a roof rake
Use calcium chloride ice melt in a nylon stocking or sock and place it across the ice dam
Create channels through the ice with a plastic shovel or ice chisel
Use warm water carefully to melt a small path for drainage
Call a professional roofing or ice dam removal service
Improve attic insulation to reduce heat loss
Seal air leaks in the attic
Increase attic ventilation
Remove heavy snow buildup from the roof after storms
Repair damaged gutters and downspouts
Install heat cables if appropriate for your roof
Address the underlying cause before the next snowfall