The best way to protect climbing roses is to bury the canes. Unhook them from whatever they are climbing on and dig a trench along the way they naturally fall and cover them over with soil. Be careful not to disturb the roots of the rose.

Mound up the soil over the canes and roses roots getting soil from somewhere else not around the rose. Then cover the mound with mulch. In the spring unmound and secure to their climbing supports and give them a spray to wash off the dirt.

Oilpainter's suggestion is right on. For borderline hardy roses, you will need to trench them.
However because you said that the roses last year got too large and toppled over a fence, it makes me wonder if what you have is a very hardy kind of rose and so wouldn't it be simpler to prune them back to a manageble size and burlap them as you had done over the years?

I tie loosely my climbing roses to the fence each spring. In the fall I untie them and lay them flat on the ground. I then cover them with burlap or landscaping fabric held in place with rocks and mulch heavily. They always survive to be picked up and tied to the fence again in the spring.

Here is a link that might be useful: My Country DIY Blog