CNN headline blames the dead (mostly former Marines) cyclists...
Daily Mail (UK) has this headline: “Seven motorcyclists are left dead and three injured in a ‘devastating crash’ after a Dodge pickup truck plows into their procession along a rural stretch of highway in New Hampshire” https://www.dailymail.co.uk/news/article-7169379/7-dead-crash-truck-motorcycles-New-Hampshire.html
Better pictures at the link.
Not only were the conditions clear and dry, it looks to be a long, straight, wide open stretch of road.