Black ice is formed by the exhaust from cars, generally found on bridges, ramps to freeways, etc. You can't see it like regular ice - so it can be dangerous. We usually don't get much up here, because the roads are treated....even with the dusting of snow today they sanded & salted intersections!
We just moved to Austin from the east coast so that we wouldn't have to deal with the snow. What happened? Our son always calls us to tell us how he is grilling on the patio and wearing shorts. He should have told us the truth earlier