Blake Harmon, 26, of Billings, was struck in the forehead by a bolt of lightning and died Saturday, his brother David Harmon said Sunday.
David Harmon, 36, said his younger brother and other family members were running to take cover from a sudden storm when he was hit about 7 p.m. at Castle Rock Park.
Blake Harmon was attending the Celebrate Freedom community gathering sponsored by Harvest Church, with his two daughters. His sisters and their families were also at the event.
There was no exit wound, and officials believe the lightning exited from a toy wagon carrying chairs and picnic gear that Blake Harmon was pulling.
Blake Harmon worked for a local heating and air conditioning company, his brother said. He is the son of Fred and Madeline Harmon of Billings.
A benefit fund is being set up at Western Security Bank, though details haven't been finalized, David Harmon said.