A frozen pipe isn't the only plumbing problem that pops up during the winter months. Freezing weather can also cause a blockage in your plumbing vents, which can not only stink up the house, but also dramatically affect how your plumbing works.
An obvious source of such problems is snow. If you live in an area with lots of snowfall, you may already be prepared for such occasions, but if you live in an area that gets hit with a winter wonderland surprise, you'll need to make sure your vents don't stay covered for long.
Not having proper venting can cause the water in your traps to get sucked out with the other water disposal (commonly called a 'dry trap'), which opens the door for sewer gases to back up out of the fixtures and into your living space. The resulting released gases not only smell bad but are actually explosive. Yes, the methane within sewer gas is quite dangerous. It's not just an urban myth. It's a problem you should take quite seriously.
Of course, snow isn't the only vent-blockage culprit. Steam from a hot shower can move up the vent pipe and freeze within the portion that extends beyond your roof. Or an under-sized vent can become blocked simply by frost within the line.
