"Many US states have loose gun ownership laws and massacres in public places are a regular occurrence."
Beer warehouse driver shoots 8 co-workers dead | The Australian
If the Australian is right, we have come to expect this violence as regular in the US. It's part of the American landscape, claims this view, for an individual to shoot several random people and then themselves as a means of dealing with some intractable problem.
It makes it sound like it's part of the weather patterns, or the migratory habits of local fauna.