But... don't use plain old salt. Use the stuff that doesn't harm asphalt (many packages say "concrete"... that is perfect). Many are just called de-icer.

Place the socks/pantyhose or even just the "salt" every four to five feet. The objective is to make a drain through, or even under, the ice so water can drain.

If you are using only de-icer, it's nice if you can make an "indentation" in the ice at the upper edge of the ice so the de-icer can lay in the indentation. Just try not to damge the roofing.

There's lots of good info at CMHC.ca

Oh... of course, if all you have is regular salt, it's better than thousands of dollars of repairs.