Colorado State Patrol trooper Nate Reed says the pickup truck was headed west on Interstate 70 near Morrison Sunday when it strayed into the eastbound lanes.
A woman whose vehicle was struck by the truck died. Six other people have been taken to a hospital with injuries.
Troopers say it’s not clear why the truck crossed into wrong-way traffic.
Colorado Department of Transportation officials warned on Twitter that any drivers traveling east on I-70 should have plenty of food and water and a full tank of gas because of delays.