I read somewhere that some3one actually tried to ignite black powder with static electricity, of the standard wool sweater in winter variety static electricity. They reported that they could not get it to ignite the powder. HOWEVER, there is standard garden variety static electricity and there is some whopper megavoltage static electricity. During the great depression in drought wind driven areas of the mid west, static electricity would build up in farm equipment (from the dust driven dry winds) strong enough to knock a man uncounsious. In Scandanavian countries cold dry winter winds against metal towers and bridge girders have been known to build up stong enough charges to kill people.
Now, North Dakota plains, colder dryer, few trees so windier, metal fence being charged by wind driven particles. I'd see that as likely to be alot more than standard wool sweater type electricity. See no problem why it couldn't ignite black powder.