A couple of things. In an urban area with a lot of trees, you could become boxed in with downed lines.

In a serious region wide storm, I could imagine help could be several days away.

Second, there are induction testers for home voltages, I can't imagine it wouldn't be possible to detect without actually touching the line.

What are the procedures used by linemen? It seems to me the would double check lines before working on them -- and possible safety measures like grounding to earth.

What are the real working parameters for safety? Is there a possibility of arcing, or is avoiding direct contact adequite?

Are the lines insulated, or no?

-john