Is it safe to have a furnaces exhaust pipe facing to the side instead of down?
You mean that the exhaust pipe is pointed towards the intake, with the idea that the heat of the exhaust will melt the snow? That is definitely not a good idea; you are correct that it could result in exhaust being pulled into the combustion air, which is not a good thing. It also risks making the problem worse -the exhaust air has close to 100% humidity, which could condense on the cold and freeze. In fact, if your intake is icing up, it's quite likely that's already the source of your problem, and you need to make sure the exhaust is further from the intake.