It's never too late to take precautions to minimize the chances that cold will damage your home.
Ice dams are most common in northern climates.
They occur when heavy snow buildup melts during the day and then refreezes when temperatures drop overnight. After several days of melting-freezing cycles, it's common for the melted water and ice to work up under the shingles until water enters the attic and eventually does damage to the ceilings, wall and contents. In cases where the ice dam goes unnoticed for an extended period of time, it can do significant damage to the building and its contents. This lets melting roof snow flow into gutters and through down spouts, just as they were designed. Make every effort to keep snow on your roof to a minimum.