Bert,
Having spent the best part of yesterday doing the exact same thing (less hitting the wires....), I can understand just how easy it is to miss seeing them. There are lines going to outbuildings or water well pumps that are impossible to see even when you know where they are and you are very close to them. The size of the wires is part of the problem...and the fact they blend into the background....throw in a very long day....old eyes....and you have the makings of such events.
A sadder story was the Weyerhaeuser 206 fatal crash of last year...those guys hit a set of wires that also killed a Bell 47 and its occupants a few years back....they remain unmarked as well.
One cannot maintain too great an awareness of wire hazards when working in hilly or forested areas.
The later account on this particular wire strike now seems to indicate a pedal turn at a hover over the orchard may have put the tail rotor into the wires....there was supposed to be wires wrapped around the remnants of the tail rotor.....I have not seen the wreckage or talked directly to anyone involved....but word travels fast around the area.
I am just glad both occupants walked away with no injuries.
