Effects of Snow on Rain Downspouts

snowy roof with gutter and downspout

The most serious effect of snow on rain downspouts is the potential formation of ice. Should this occur, melting snow water may have nowhere else to go but up and underneath the shingles on the lower part of the roof. If left unattended, this can damage not only the shingles, but the roofing paper and wood sheathing as well. This can lead to leaks that require expensive repairs. Another possible effect of persistent snow in the gutters and downspouts is the sheer weight it puts on the structure. Over time this can weaken their supports and cause them to break off.


Downspouts are the vertical portion of metal or plastic piping extending to the ground from the gutters. Their purpose is to channel water that runs into the gutters down either onto the ground or into the storm drain. In either case the water must be directed away from the home’s foundation to prevent damage there. In the event of a deluge or a heavy storm, often times the downspouts become overwhelmed with water and cease to function properly. They are prone to clogging, especially if there are trees immediately above them.

Snow in the Gutters and Downspouts

When snow falls, provided the temperature stays low, it typically hangs around for awhile. If it warms up a little during the day but then refreezes at night, what snow was able to melt can freeze again and turn to ice. This can be a problem for both gutters and downspouts. As ice begins to form in the gutters and the entrance to the downspouts, it blocks the passage of other water that would otherwise melt and flow down it. If this water has nowhere to go, it will eventually amass and creep back from the gutters and work its way underneath shingles. This is called an ice dam formation. The ice in effect dams the water and creates a reservoir between the ice and the roof. Once this happens, serious water damage can happen to the roof.

What to Do

A little snow on the roof and in the gutters won't cause much harm. Homeowners in colder regions have the most reason to be concerned, because the snow can last for a long time. This can cause ice to build up in the gutters and on top of the downspouts, forming ice dams and adding weight. In colder regions, snow should be pulled off the roof with a snow remover attached to a long pole. Homeowners can then reach the edge of the roof from the ground. If ice has already started to form around the gutters or downspouts, melting it promptly is another option. This can be accomplished with a special ice melter or by using a do-it-yourself remedy such as rock salt.

Don’t let excess snow have any negative effects on your home’s gutters or downspouts. If ice is allowed to form around them, it can cause damage that requires costly repairs. For residents of cold weather regions, this is an annual battle that must be fought with Mother Nature.