I just heard about this nearly a week later from Beau of the Fifth Column.
Apparently around midnight on July 4, a woman was held at gunpoint by a man at Yellowstone National Park, where he told her he was going to commit a mass shooting. Somehow she got away from him, and alerted park rangers, who confronted him eight hours later when he came to shoot up a restaurant that had 200 people in it.
One park ranger was injured, and the shooter was killed on scene.
This was almost the worst Fourth of July ever.