The roof shingles should be softened and flattened as the shingles tend to curl up in winter.
How to fix a leaky roof in winter.
Your best solution may be to just tarp off the problem area until the spring but be sure not to block off any venting pipes that vent out dangerous gasses.
This step ensures the tarp stays taut and fully protective.
Locate the source of the leak by examining the underside of the roof from within your attic or crawl space.
This will freeze the leaking water in place but you ll still need to deal with the ice dam or it will melt and start leaking again.
Shine a flashlight along the underside of the roof and look for a hole in the roof as well as areas that are wet or have been.
Locate the leaking source and search for the damaged or missing shingles and make a list of the areas to be repaired.
The shingles can be warmed up with a propane torch.
The purpose is to keep the shingle tabs down in high winds.
Recaulk the corner flashing if any areas have hardened caulk.
Isolate areas when you run the hose.
Fix this board to your roof using a screw as a temporary anchor.
Start low soaking the area just above where the leak appears in the house.
For example soak the downhill side of a chimney first then each side then the top on both sides.
Now is a time when you can start planning if you know where to start.
If you plan to replace shingles in the winter it can be done but you have to add something to bond the shingles together.
If a leak is difficult to find enlist a helper and go up on the roof with a garden hose.
The board must be 2 feet longer than the tarp s width and it should sit against the roof to avoid the collection of rainwater snow or debris.
Replace any missing or rotted siding above the step flashing on dormers.
You can t fix a leaky roof from the inside so don t even try.
How to repair a leaky roof from inside the house.
Sandwich the tarp by nailing a second 2 x 4 board to the first.
Make use of the flame carefully on the curled shingle edges.
To stop the leak use a long handled roof rake to remove snow from your roof or blow cold air onto the area of the roof that is leaking in your attic using a box fan.
Identify the potential source of the leak.