Public Power, Jul/Aug 2014, by Brent Barker.
http://www.publicpower.org/Media/magazine/ArticleDetail.cfm?ItemNumber=41392

"After every storm that leaves the overhead electric distribution system in shambles, the inevitable question arises: “Why not put it underground?” The fervor usually cools once the parties begin to look at costs. Undergrounding remains an expensive proposition—about three to five times the cost of overhead."