The thing to keep in mind about black ice is that it's different than normal cold weather ice or icy roads in general.

Black ice forms only within a narrow temperature band near 32F. (lower on salted roads). There are many techniques for riding safely on icy roads, but black ice hazards relate to riding on roads that are generally clear or unfrozen. So it's the element of surprise that creates the greatest danger.

Sometimes you'll see black ice even when it's above freezing and you have no reason to expect it. For example after a bitter cold spell road surface temperatures can vary greatly. The sun warms most of the road, but a section shaded by buildings may stay colder, so melt across the road freezes on contact. If the ice patch is short enough you'll be past it and able to recover before you go down, but a long patch on the north side of a tall building can nail you when you least expect it.