Just keep in mide, it is a SNOW blower, not ICE blower. Made for comsumer user. I wouldn't recommand you to blow the ice curb the city left to you at the end of your drive way if it's full of ice. It is so easy to damage the impeller of your machine. To replace it will cost you more than half the price of the whole blower.
Metal Shovel is the only cost effective solution for the ice dam, since the ice dam is hard and heavy. Too bad the city leave it to you.
If you don't care about the cost, you can always hire someone to do the removel.