I know I wouldn't be out looking any time soon, after a Hurricane or tornado passes through. Fortunately, its been about 10 years now, since any major destruction. First couple of weeks, people are pretty much stunned, and drained. Just too busy with their own losses, and messes to clean up, figure out the repairs, replace. I know driving around collecting scrap can get you into some trouble, least detained on the side of the road for a while.
Not always easy to determine property boundaries, trespassing could get you shot. Got to remember, folks from FEMA and insurance companies need to look things over. Think it would mostly be a trash-fest, finding good stuff would mostly be luck, and the detector would be of little help. You'd do better on eyeball finds. Really unbelievable how destructive these storms really are, until you've walked around after one.