Go to this you tube video to understand how ice dams are created and the damage they can do. https://www.youtube.com/watch?v=QsvZ3OGJp5Y
It is important to routinely remove snow from your roof and check for signs of ice blockages. Roof rakes are helpful for removing several inches of snow from the edges of your roof and with extension handles can be used from the ground and not on a ladder. Ice Dams can cause serious damage to your property. I speak from experience as I had an ice dam cause several thousands of dollars in damage to my ceiling, floors and walls. It is something to take seriously when you see one forming on your home. An ice dam is formed on a slanted roof when heat from the attic causes the snow on the roof to melt. Melted snow flows down the roof and then will freeze again when it meets colder air at the edge of the roofline. Once the ice reforms it keeps additional water from draining off the roof. The water then builds up behind the ice dam where in can seep under the shingles and flow right into your house.
You can tell if you have an ice dam by looking for a lot of thick ice or large hanging icicles on your roof. You may also see ice your downspouts or guttering. Ice dams can happen at any point in the season so be vigilant about checking your property and being on the look-out for any signs that problems could be starting to arise. Contact a professional to help you remove the ice dams as it is dangerous to be up on your roof in icy conditions. You are also risking damaging your roof if you do not remove the ice properly.
In my experience damage from ice dams can be devastating. Know what to expect and how to prevent them. Chelsea Mayer
For a great source of additional information check out the Ice Dam Guys www.icedamremovalguys.com