There's never a good time to have your roof leak or develop a hole, but winter is certainly the last season during which you want to have roofing problems. The water that comes in will damage your insulation when you need it most, and it will be hard for contractors to get on the roof with the snow. Luckily, you can decrease your chances of a winter roof calamity by taking these steps before the cold weather really sets in.
Trim the trees.
When tree branches get weighed down with ice and snow in the winter, they can easily snap and fall on your roof, leading to shingle damage or bent gutters. If there are any trees overhanging your roof (or even near it) have a tree care expert come trim away any dead or damaged branches now.
Check the gutters.
Leaves often start clogging the gutters in the fall. When winter hits, the mixture of leaves and water freezes. This prevents any melted snow from leaving the roof, so water builds up, eventually causing leaks. Cleaning gutters is easier than you might assume. You just put a glove on and scoop the debris out. If you want to be really thorough, you can then rinse the gutter out with a hose or a pitcher of water. Also make sure none of your gutters are bent, as this can affect their capacity and ability to drain. If they do appear bent, you can typically use your (gloved) hands to straighten them back out again. Finally, make sure the fasteners that connect the downspouts to the gutters are tightened properly.
Check for exposed nail heads.
When a roof is assembled correctly, all of the nail heads should be covered by the layer of shingles above them. However, if your roof was ever patched or the roofing company was not at the top of their game that day, you might have some exposed nail heads. If a little water seeps in around these nail heads and expands, it can create bigger holes that then start to leak. So, climb on a ladder and scan your roof for any nail heads. If you see them, use a hammer to pound them down until they're flush with the roof. Then, apply a glob of roofing cement to the nail head. (Roofing cement is readily available at most hardware stores.)
For more advice on preparing your roof for the winter, talk to a roofing contractor in your area.