If an ice dam has formed, leaving icicles hanging along the eaves of your house/building, it’s time to look at removal before damage occurs to the gutters and shingles, or even worse, water entering the house, causing ceiling and paint damage.
To Get Rid of Ice Dams Fast:
Blow cold air into attic.
Rake snow off the roof if you can safely do so.
De-ice using Calcium Chloride de-icer
You can fill a pantyhose with de-icer and place across ice dam to slowly melt the ice in the gutter.
For more information on prevention and removal: https://www.thisoldhouse.com/roofing/21017660/how-to-get-rid-of-ice-dams
Disclaimer: please discuss with a roofing professional prior to attempting ice removal to ensure the removal type is appropriate for your property.